TY - JOUR
AU1 - Bi, Lei
AB - INTRODUCTION History Institute of Metal Research (IMR), which was founded in Shenyang in 1953, is among the earliest institutes established by the Chinese Academy of Sciences (CAS) subsequently to the founding of the People's Republic of China (PRC). Prof. Lee Hsun (H. Lee), a prominent physical metallurgist, was appointed as the first director of IMR by Premier Zhou Enlai of the State Council of PRC. Since its founding, IMR has been focusing on the technology demands of the country, and playing a leading role in developing early technologies. IMR also studied industries projects for national recovery in the iron and steel industries such as hydrogen in steels, together with many other related industries. After accomplishing its mission during the national recovery stage, IMR extended its research during the 1960s by developing new materials, including superalloys and refractory metals, and technologies, to fulfill the requirements of the national aerospace industry. IMR has developed the high-performance Nb- and Mo-based alloys which were successfully applied in national satellite projects. It should be highlighted that IMR’s technological breakthrough of casting hollow blades for aero engines served as a benchmark of the national strategy, which was later recognized with the first class prize of the National Science and Technology Progress Award. In the 1980s, IMR expanded its vision to materials science and engineering, which remains a focus today. The focus of materials research has changed from solely emphasizing materials technologies that meet urgent domestic needs to balanced studies of both materials science and technology. In 2000, the Shenyang National Laboratory for Materials Science (SYNL) was founded at IMR by the Ministry of Science and Technology of China. IMR also built three technological centers, focusing on the studies for materials technologies. A series of important technologies related to metallurgical purification, precision casting, welding, pipe processing, and the preparation of composite materials were successfully developed to address industrial demands. One of the technological breakthroughs at IMR during this period was the innovative application of mining drill materials that received a first class prize of the National Science and Technology 
Progress Award. Academic recognition IMR has a strong research team including the members from the CAS and the Chinese Academy of Engineering (CAE) and has played a leading role in the materials research in China over the past 60 years. IMR receives world-wide recognitions due to its excellence in the research filed of materials science and engineering, becoming an indispensable base for materials science and engineering research in China. Financial support The research activities are well financially supported at IMR. The financial support that IMR has gained from 2011 to 2015 steadily increased with an average increment rate of 12% per year. IMR has received 1 billion CNY of financial support in 2015, including the support from the CAS projects, the National Natural Science Foundation of China projects, the Ministry of Science and Technology projects, the local government/enterprise/universities projects and the international projects as along with the income from technology transfer. The excellent research teams coupled with sufficient financial support and great research facilities enable IMR to continue the success in the research of materials science and engineering. Organization and structure IMR is now committed to building a world-class multidisciplinary institute by prioritizing the R&D of key metallic structural materials while encouraging the research of advanced functional materials. The aim of IMR is to seek to resolve major materials issues of national needs while remaining original and innovative, and to expand the scientific horizons of materials R&D. Open in new tabDownload slide Open in new tabDownload slide FACT at a glance for Institute of Metal Research MAJOR RESEARCH FIELDS The research activities at IMR primarily aim to serve the national needs for advanced structural materials research in superalloys, titanium alloys, and high-performance steels. Additionally, IMR emphasizes the promotion of vast and intensive research on core scientific problems, and crucial technological problems in the field of materials science and technology. Three featured research areas at IMR are introduced here. High-temperature structural materials for advanced propulsion and power systems IMR, which plays a leading role in the R&D and processing in fields related to superalloys and titanium alloys, has addressed a series of critical materials and bottleneck technologies during the Twelfth 5-Year Plan period of China, including the second-generation single crystal superalloys and blade manufacturing, the thermal corrosion-resistant superalloys, the wrought alloys for turbine disks, the manufacturing technology for large-sized hollow blades, the high-temperature titanium alloys and the integrated manufacturing processes for blisks, intermetallic alloys based on the Ti-Al system and corresponding manufacturing processes, large-sized isotropic graphite, and connecting technology for heterogeneous materials. Corrosion protection technologies in major engineering projects To meet the industrial demand against natural environmental corrosion, a variety of advanced corrosion protection techniques have been developed in IMR, such as a series of high-performance coating, plating, and cathodic protection techniques, and corrosion monitoring and detection through fundamental research on corrosion science covering electrochemical corrosion, high-temperature oxidation, and environment-sensitive fracturing. All of these techniques have been successfully applied to practical engineering projects, such as cross-sea bridges, oil pipelines, large-scale water conveyance pipelines, aero engines, industrial gas turbines, and aircraft engineering. With the unique advantage of retaining the top position in the metal corrosion and protection research field, IMR was awarded the Distinguished Organization Award by the National Association of Corrosion Engineers (NACE International) in 2011. Nanostructured engineering metallic materials: Fundamental research and technologies Over the past few years, new nanostructures (such as the nanotwinned structure and gradient nanostructure) have been developed in IMR, which allow the achievement of high strength in metals without compromising the corresponding ductility or other properties. In-depth studies have provided new insights into the comprehension of intrinsic mechanical behavior and underlying deformation mechanisms of nanostructured metals. These new scientific findings and technologies that have been developed at IMR have attracted great interest worldwide, leading to a profound impact on the development of high-performance engineering metallic materials High-temperature structural materials for advanced propulsion and power systems IMR, which plays a leading role in the R&D and processing in fields related to superalloys and titanium alloys, has addressed a series of critical materials and bottleneck technologies during the Twelfth 5-Year Plan period of China, including the second-generation single crystal superalloys and blade manufacturing, the thermal corrosion-resistant superalloys, the wrought alloys for turbine disks, the manufacturing technology for large-sized hollow blades, the high-temperature titanium alloys and the integrated manufacturing processes for blisks, intermetallic alloys based on the Ti-Al system and corresponding manufacturing processes, large-sized isotropic graphite, and connecting technology for heterogeneous materials. Corrosion protection technologies in major engineering projects To meet the industrial demand against natural environmental corrosion, a variety of advanced corrosion protection techniques have been developed in IMR, such as a series of high-performance coating, plating, and cathodic protection techniques, and corrosion monitoring and detection through fundamental research on corrosion science covering electrochemical corrosion, high-temperature oxidation, and environment-sensitive fracturing. All of these techniques have been successfully applied to practical engineering projects, such as cross-sea bridges, oil pipelines, large-scale water conveyance pipelines, aero engines, industrial gas turbines, and aircraft engineering. With the unique advantage of retaining the top position in the metal corrosion and protection research field, IMR was awarded the Distinguished Organization Award by the National Association of Corrosion Engineers (NACE International) in 2011. Nanostructured engineering metallic materials: Fundamental research and technologies Over the past few years, new nanostructures (such as the nanotwinned structure and gradient nanostructure) have been developed in IMR, which allow the achievement of high strength in metals without compromising the corresponding ductility or other properties. In-depth studies have provided new insights into the comprehension of intrinsic mechanical behavior and underlying deformation mechanisms of nanostructured metals. These new scientific findings and technologies that have been developed at IMR have attracted great interest worldwide, leading to a profound impact on the development of high-performance engineering metallic materials Open in new tab High-temperature structural materials for advanced propulsion and power systems IMR, which plays a leading role in the R&D and processing in fields related to superalloys and titanium alloys, has addressed a series of critical materials and bottleneck technologies during the Twelfth 5-Year Plan period of China, including the second-generation single crystal superalloys and blade manufacturing, the thermal corrosion-resistant superalloys, the wrought alloys for turbine disks, the manufacturing technology for large-sized hollow blades, the high-temperature titanium alloys and the integrated manufacturing processes for blisks, intermetallic alloys based on the Ti-Al system and corresponding manufacturing processes, large-sized isotropic graphite, and connecting technology for heterogeneous materials. Corrosion protection technologies in major engineering projects To meet the industrial demand against natural environmental corrosion, a variety of advanced corrosion protection techniques have been developed in IMR, such as a series of high-performance coating, plating, and cathodic protection techniques, and corrosion monitoring and detection through fundamental research on corrosion science covering electrochemical corrosion, high-temperature oxidation, and environment-sensitive fracturing. All of these techniques have been successfully applied to practical engineering projects, such as cross-sea bridges, oil pipelines, large-scale water conveyance pipelines, aero engines, industrial gas turbines, and aircraft engineering. With the unique advantage of retaining the top position in the metal corrosion and protection research field, IMR was awarded the Distinguished Organization Award by the National Association of Corrosion Engineers (NACE International) in 2011. Nanostructured engineering metallic materials: Fundamental research and technologies Over the past few years, new nanostructures (such as the nanotwinned structure and gradient nanostructure) have been developed in IMR, which allow the achievement of high strength in metals without compromising the corresponding ductility or other properties. In-depth studies have provided new insights into the comprehension of intrinsic mechanical behavior and underlying deformation mechanisms of nanostructured metals. These new scientific findings and technologies that have been developed at IMR have attracted great interest worldwide, leading to a profound impact on the development of high-performance engineering metallic materials High-temperature structural materials for advanced propulsion and power systems IMR, which plays a leading role in the R&D and processing in fields related to superalloys and titanium alloys, has addressed a series of critical materials and bottleneck technologies during the Twelfth 5-Year Plan period of China, including the second-generation single crystal superalloys and blade manufacturing, the thermal corrosion-resistant superalloys, the wrought alloys for turbine disks, the manufacturing technology for large-sized hollow blades, the high-temperature titanium alloys and the integrated manufacturing processes for blisks, intermetallic alloys based on the Ti-Al system and corresponding manufacturing processes, large-sized isotropic graphite, and connecting technology for heterogeneous materials. Corrosion protection technologies in major engineering projects To meet the industrial demand against natural environmental corrosion, a variety of advanced corrosion protection techniques have been developed in IMR, such as a series of high-performance coating, plating, and cathodic protection techniques, and corrosion monitoring and detection through fundamental research on corrosion science covering electrochemical corrosion, high-temperature oxidation, and environment-sensitive fracturing. All of these techniques have been successfully applied to practical engineering projects, such as cross-sea bridges, oil pipelines, large-scale water conveyance pipelines, aero engines, industrial gas turbines, and aircraft engineering. With the unique advantage of retaining the top position in the metal corrosion and protection research field, IMR was awarded the Distinguished Organization Award by the National Association of Corrosion Engineers (NACE International) in 2011. Nanostructured engineering metallic materials: Fundamental research and technologies Over the past few years, new nanostructures (such as the nanotwinned structure and gradient nanostructure) have been developed in IMR, which allow the achievement of high strength in metals without compromising the corresponding ductility or other properties. In-depth studies have provided new insights into the comprehension of intrinsic mechanical behavior and underlying deformation mechanisms of nanostructured metals. These new scientific findings and technologies that have been developed at IMR have attracted great interest worldwide, leading to a profound impact on the development of high-performance engineering metallic materials Open in new tab RECENT RESEARCH HIGHLIGHTS Exploration of the atomic-scale information for materials New understanding of pitting initiation of austenitic stainless steels Stainless steels are widely used in modern life for their superior corrosion resistance. However, they are susceptible to the localized pitting corrosion in the presence of aggressive anionic species, which is one of the major causes of materials’ failure and hence leads to a huge loss to society. The pitting event is generally believed to originate from the local dissolution in MnS inclusions which are more or less ubiquitous in stainless steels. However, the initial location where MnS dissolution preferentially occurs is known as unpredictable, which makes pitting corrosion remain a big problem for stainless steels. Prof. Xiu-Liang Ma and his colleagues applied in-situ ex-environment transmission electron microscopy (TEM) and found a number of nano-sized octahedral MnCr2O4 crystals embedded in the MnS medium, generating local MnCr2O4/MnS nano-galvanic cells. The TEM experiments combined with first-principles calculations clarified that the nano-octahedron, enclosed by eight {111} facets with metal terminations, acts as the reactive site and catalyzes the dissolution of MnS. This study uncovers the origin of MnS dissolution in stainless steels and provides a new basis for understanding pitting corrosion of stainless steels (Fig. 1). Figure 1. Open in new tabDownload slide Left panel: Composition analysis of a nano-MnCr2O4, around which MnS dissolution occurs in the presence of salt water. (a) HAADF STEM image showing a pit in MnS around a particle. (b) EDS results of a scan made along the red line in (a). The pit contributes little to MnS signals, providing a clear imprint of MnS dissolution. (c, d) EDPs obtained from the particles shown in (a). Right panel: Identification of an octahedron by means of large-angle tilting experiments and 3D tomography. The octahedron is enclosed by eight triangles labeled I, II, III, IV, V, VI, VII, and VIII, respectively. Reprinted with permission from Elsevier. Based on the above new mechanism, Prof. Xiu-Liang Ma and his colleagues have demonstrated that the MnCr2O4/MnS galvanic corrosion can be greatly resisted by bathing the steels in Cu2+–containing solutions. This chemical bath generates a thin film of Cu2−δS layers on the exposed surfaces of MnS inclusions. Such chemical coating leads to the inactivation of anodic MnS inclusions and prevents the nano-galvanic cells from electrochemically working, thus significantly enhancing the pitting resistance of austenite stainless steels. The study provides a low-cost approach via atomic-scale coating to improve the pitting corrosion resistance of stainless steels in a volume-treated manner. Discovery of full flux-closures in ferroelectrics Nanoscale ferroelectrics are expected to exhibit various exotic domain configurations, such as the full flux-closure pattern which physicists predicted three decades ago. These flux-closure domains should be switchable and may give rise to an unusually high density of bits as well as undergo vortex-polarization phase transformation. They are also potentially useful as mechanical sensors and transducers. Similar domains are well known in ferromagnetic materials, and their topological properties and dynamics are under intense investigation. However, in ferroelectric materials, particularly in tetragonal ferroelectrics, the coupling of polarization to spontaneous strain would be so pronounced that formation of a closure-quadrant with its resultant severe disclination strains could be impossible. Prof. Xiu-Liang Ma and his colleagues have made a breakthrough on this research topic. By engineering strain at the nanoscale, they grew PbTiO3/SrTiO3 multi-layer films on a GdScO3 substrate. Using aberration-corrected scanning transmission electron microscopy, they observe not only the atomic morphology of the flux-closure quadrant but also a periodic array of flux-closures in ferroelectric PbTiO3 films, mediated by tensile strain on a GdScO3 substrate. They directly visualize an alternating array of clockwise and counter-clockwise flux-closures, whose periodicity depends on the PbTiO3 film thickness. In the vicinity of the core, the strain is sufficient to rupture the lattice, with strain gradient up to 109/m. Away from the vertex, the strain gradient estimated in the triangle domain is about 4 × 106/m. A flexoelectric coefficient as giant as 10–10 C–1m3 is also derived (Fig. 2). The results provide a new similarity between ferroelectric and ferromagnet, and extend the potential of employing epitaxial strain for modulating ferroelectric domain patterns. Designs based on controllable ferroelectric closure-quadrants could be fabricated for investigating their dynamics and flexoelectric responses, and in turn assist future development of nanoscale ferroelectric devices such as high-density memories and high-performance energy-harvesting devices. Figure 2. Open in new tabDownload slide Long-range periodic disclination pairs in the ferroelectric PbTiO3 film (Left panel). Atomically resolved HAADF-STEM images corresponding to the areas labeled as 1, 2, 3 and 4 in D of the left panel. The red and yellow circles denote the positions of Ti4+ and Pb2+ columns, respectively. Arrows denote reversed Ti4+ displacement directions (Right panel). Reprinted with permission from AAAS. Nanostructured metallic materials The traditional strengthening methods have to compromise material properties, which may prevent many high-strength materials from practical applications. In the past decade, pioneering work has been carried out at IMR to develop two types of laminated nanostructures and propose a new strategy for forming gradient nanostructures that are able to strengthen metals with preserved (even increased) ductility, electrical conductivity, and thermal stability. These findings pave the way for developing high-performance metallic materials with optimized global properties, also constituting IMR as a leading research institute at this field in the world (Fig. 3). Figure 3. Open in new tabDownload slide Schematic illustration of examples of structural modifications for strengthening metals and alloys. Reprinted with permission from AAAS. Nano-twinned metals: nano-laminated structure with twin boundaries (TBs) By using pulsed electro-deposition, high-density nano-scale growth twins were engineered into pure Cu thin film samples. These samples exhibit ultrahigh strength and excellent electrical conductivity, which might be originated from the effective blockade of dislocation motion by high-density coherent nanoscale TBs with an extremely low electrical receptivity. The tensile strength approaches 1068 MPa, which is one order of magnitude higher than the conventional coarse-grained copper. The electrical conductivity of nano-twinned Cu (97% IACS) is comparable to the coarse-grained high-conductivity copper, which is remarkable because the traditional strengthening approaches generally reduce the electrical conductivity, due to a scattering barrier increase. With decreasing twin thickness, the increase in the strength of nano-twinned Cu is accompanied by simultaneous increases in tensile ductility, strain hardening ability, fatigue strength, strain rate sensitivity, and resistance to crack propagation, in sharp contrast to the reductions of fine-grained counterparts with conventional large-angle GBs. These extraordinary properties of the nano-twinned materials originate from the dislocation-TB interactions that fundamentally differ from dislocation-GB interactions in nano-grained and coarse-grained metals. The presence of nanoscale TBs can provide an adequate barrier to dislocation motion for strengthening and create more local sites for nucleating and accommodating dislocations, thereby increasing the ductility and the work hardening. Owing to the low interface energy of TBs, the thermal stability of nano-twinned metals is quite higher than the nano-grained metals. This provides an opportunity to achieve small and stable twinned structures at room temperature. As expected, the resultant nano-twinned Cu has a mean twin thickness (λ) in the range of 4–100 nm, whereas the grain size is maintained within the submicron scale. As the thickness decreases to 15 nm, the strength reaches a maximum. The ductility and work hardening ability were also found to increase monotonically as the λ decreases. At the λ < 10 nm, the work hardening exponent is even higher than that of the coarse-grained counterpart, demonstrating the super-high strain hardening ability of the nano-twinned Cu. The occurrence of maximum strength in the nano-twinned Cu could be attributed to a transition of the dominant plastic deformation mechanism from the dislocation-twin boundary interactions to the slip of the preexisting dislocations on twin boundaries. Large-scale molecular dynamics simulations and a kinetic theory of dislocation nucleation in nano-twinned metals also display the existence of a transition in the deformation mechanism that occurs at a critical twin-boundary spacing, where the strength is maximized. At this point, the classical Hall-Petch type of strengthening caused by dislocation pile-up and cutting through twin planes switches to a dislocation–nucleation-controlled softening mechanism with twin-boundary migration that results from the nucleation and motion of partial dislocations in parallel to the
 twin planes. Nano-laminated structure with low-angle boundaries The surface mechanical grinding treatment (SMGT) is a technique developed at IMR involving high-speed shear plastic deformation with a large strain, high strain rate, and large gradient of the shear strain, which allows the fabrication of surface layer of 2D nanolaminated (NL) structures pure Ni. The overall thickness of the obtained NL layer could reach 80 nm. The average lamellar thickness of the NL structures is as low as 20 nm, which is one order of magnitude lower than the size limit during the traditional severe plastic deformation. The NL structures are strongly textured with a mainly low misorientation angle (< 10 degrees) across the lamellar boundaries. These NL structures demonstrate ultrahigh hardness and high thermal stability. These NL structures show ultrahigh hardness (6.4 GPa) that is far above the hardness (∼3.0 GPa) of ultrafine-grained (UFG) structures. Meanwhile, the NL structure shows high thermal stability, whose onset temperature for structural coarsening is ∼ 40°C higher than that of UFG counterparts. The combination of the high hardness and high thermal stability of such 2D NL structures breaks the trend-off relationship between the strength and the stability for traditional metallic materials and provides new insights for the development of high–performance metallic materials, particularly in alloying systems where the stacking fault energy is high and the formation of nano-twinned structures is unfavorable (Fig. 4). Figure 4. Open in new tabDownload slide (A) Schematic illustration of the SMGT set-up. (B) Cross-sectional SEM image of the SMGT Ni sample, in which the treated surface is outlined by a yellow dashed line. (C) EBSD image of the region outlined by the blue dashed line in B. (D, E) Typical bright-field (BF) cross-sectional (SD-ND) and longitude-sectional (TD-ND) TEM images of the UFG structures (110 mm deep from the surface) and NL structures (40–50 mm deep from the surface) indicated in B, respectively. Insets in (D) and (E) are the corresponding distribution of boundary spacing (left) and SAED pattern (right). The sample coordinates in D and E are identical to those in A. (F) Dark-field longitude-sectional TEM image corresponding to that in E. Reprinted with permission from AAAS. Gradient nanostructures The surface properties of a material are decisive for its service life and the surface treatment which is an important branch of materials science have been extensively studied to improve the global performance by enhancing material surface properties. However, traditional approaches for the improvement of surface properties have encountered certain problems in applications, such as poor binding between the coating and base material, the coating material peel-off and the high reaction temperatures. A group led by Prof. Ke Lu at IMR has proposed the concept of “surface nanocrystallization” to solve these problems. The idea is to introduce a layer of nano-grained structure in the material surface, with gradual structure size (grain size) changes from the surface (nanometer-scale structure) to the interior (coarse structure). Such a surface layer has a perfect binding with the base material, and no peel-off phenomena. The surface nanocrystalline layer is observed to have excellent mechanical properties and wear resistance, favoring diffusion and chemical reactions. Furthermore, the surface nanocrystallization is achieved by mechanical means that are simple, cost-effective, and suitable for most metallic materials. By combining the surface nanocrystallization processing and the conventional surface chemical heat treatment (such as nitriding, chromizing, and aluminizing), the temperatures that are required for nitriding and aluminizing treatments were dramatically decreased in iron and steel, which greatly broadened the applicable temperature range of these chemical treatments. As an example, the gaseous nitriding temperature of iron could be decreased from > 500°C to 300°C when the surface nanocrystallization is introduced prior to the nitriding treatment. This great achievement was selected as one of the Top Ten Progresses of Science and Technology in China 2003. Several new processing technologies, such as Surface Mechanical Attrition Treatment (SMAT) and Surface Mechanical Grinding Treatment (SMGT), have been developed at IMR for preparing the gradient nanostructure surface layer in metallic materials and these techniques are utilized by more than 10 institutions and companies in China, United States, France, Germany and Australia. Unified fracture criterion for high-strength materials In past decades, many emerging structural materials with very high strength have been well developed, such as metallic glasses (MGs) and nanocrystalline materials. However, one common major drawback in these high-strength materials is the lack of plasticity, which often induces catastrophic brittle fracture under some stress states especially with tensile stresses. Predicting the brittle fracture under dangerous stress state and avoiding the fracture disaster by safety design of structural components require applicable fracture criterion. Traditional criteria usually deal with materials with low or medium strengths, which were found unable to explain the strength and fracture of the new high-strength materials. Prof. Zhe-Feng Zhang and his colleagues have developed a new unified fracture criterion (also called as the ellipse criterion, see Fig. 5(a)), i.e. (σ/σ0)2 + (τ/τ0)2 = 1, which is capable of unifying several classical strength theories in the textbooks of past three centuries. The validity of this criterion has been well verified by examining the critical fracture conditions of MGs under complex stress states and the tension-compression strength asymmetry of various high-strength materials. Furthermore, the ellipse criterion can be deduced from a generalized energy failure criterion (see Fig. 5(b)), i.e. (Es/Es0) + (Ec/Ec0) = 1, which illustrates materials’ failure as an energetic competition between the two basic failure mechanisms of shear and cleavage. Based on the ellipse criterion, they can also precisely predict the fracture conditions and behaviors of MGs only from elastic constants, achieving the first real-sense non-destructive failure prediction in various MGs (see Fig. 5(c)). The studies advance the development of strength theories of materials, and provide instructions for predicting the fracture behaviors of MGs and other high-strength materials as well as for ensuring the safe utilization of components. Figure 5. Open in new tabDownload slide Critical fracture loci of a metallic glass predicted by (a) the ellipse criterion, (b) the generalized energy criterion and (c) the formula with only elastic constants based on the unified criterion. Reprinted with permission of AIP Publishing. Net-shape casting of TiAl low-pressure turbine blades The reduction of flight emission is a global target and the weight reduction of aero engine components is key to achieving this goal. The replacement of superalloys with intermetallic TiAl alloys could achieve a 50% weight reduction in the turbine blades and would also lead to a significant weight reduction of turbine disks, as demonstrated by the successful application of 4822 (Ti-48Al-2Cr-2Nb) TiAl alloy in making low pressure turbine blades for GEnx engines. However, its current manufacturing method is quite expensive. In contrast, 4522XD (Ti-45Al-2Mn-2Nb-1B) is considered to be more suitable as a cast alloy because it exhibits a weak casting texture and has fine grain size. The key difficulties to overcome for 4522XD alloy include the precise control of the content of volatile alloying element Mn, and of the morphology of the boride particles which is crucial for grain refinement. Aiming to solve these problems, systematic and in-depth investigations on TiAl alloys have been performed by a group led by Prof. Rui Yang in the Titanium Alloys Division at IMR, and three pivotal technologies enabling a net-shape manufacturing process of TiAl blades have been developed (Fig. 6). Figure 6. Open in new tabDownload slide Cast TiAl low pressure turbine blades (left); Rolls-Royce presenting certificate to IMR approving TiAl casting technology for low-pressure turbine blades (right). Preparation of industrial-scale casting stock: Key issues such as electrode welding, control of manganese concentration and boride morphology, and avoidance of high density inclusions of niobium and even of titanium in 4522XD alloys were solved. A process to produce industrial-scale 4522XD casting stock was developed and certified by Rolls-Royce in 2011. Development of high-stability face coat of shell mold: A core technology in casting net-shape TiAl turbine blades is to minimize the chemical reaction of Ti with shell mold that contaminates the aerofoil surface, due to the high reactivity of titanium once melted. A suitable slurry for the shell mold face coat has been developed which is stable enough to be suitable for continuous production of shell molds. Minimizing casting defects: Metallurgical defects of cast turbine blades such as surface porosity and inclusions degenerate mechanical properties and must be strictly controlled. By combining computer simulation and experimental studies, a processing window has been identified to cast net-shape blades that meet the requirements for practical applications. Full sets of low pressure turbine blades supplied to Rolls-Royce have passed 1750 simulated flight cycles of engine test on a Trent XWB test bed in 2014. Visual casting and forging technology Heavy castings and forgings are key components for major engineering projects. Visibility of this process would fundamentally change the process design from the experience-based to the science-based. Has focused on this industrial demand, Prof. Dian-Zhong Li's group at IMR performed systematic investigations on the metal-forming capabilities of heavy sections, defects, and microstructure evolution using computer simulation in conjunction with real-time X-ray scanning under scaled trials with sections. To date, several new processing technologies (e.g., a steady pouring technique for heavy castings, an alloying phase quantitative control technique, and a near net forming technique) have been developed, and a complete prototype technology that includes drawing sheet, specifications, and software has been compiled for hot-working factories. Casting of back-up rolls for steel mills is one case can be highlighted. Through computer simulations and real-time X-ray scanning, the distribution of temperature, stress and microstructural evolution during metal pouring and solidification, which enable the prediction of pores and shrinkage, have been investigated. Based on these simulated results, several novel techniques for the quality optimization of the casting have been proposed: (1) a breakthrough steady pouring and filling system for the molten steel purity to be ensured, (2) a stress-releasing system that may eliminate thermal cracking by using a slide journal device and (3) a subsequent cooling and solidification system, which may ensure the internal quality of the casting. An integrated technology has been developed with detailed casting parameters and die design drawings, which have been successfully applied in the Chinese First Heavy Machinery Company and the Angang Heavy Mechanical Company for casting rolls production that ranges from 50 tons to 100 tons. Certain other achievements of heavy castings and forging manufacturing include the stainless steel turbine runner for the Three Gorges Project, the 90 type marine crankshafts, the high-speed train bogies, the conical shells for nuclear power plants, and the large valves for thermal power plant. IMR has also provided technical guidance and specifications for castings manufacturing of hydroelectric turbine runners and CRH 5 Multiple Units train bogies. All these applications leads to high industry revenues and demonstrate that the academic research at IMR has improved the level of casting and forging technology in China, enhancing the national industrial competence, which sets a good example of the collaboration between the academic institutes and the pertinent industries (Fig. 7). Figure 7. Open in new tabDownload slide Stainless turbine runner (450 ton weight, 10 m diameter) for Three Gorges hydroelectric power station (a); Large marine crankshaft (200 ton weight, 16 m length) (b); Conical shell forging for steam generator for AP1000 (reactor) nuclear power plant (c, d). Open in new tabDownload slide INTERVIEW NSR: What is it like working in the center? Open in new tabDownload slide Rui Yang: Director of Institute of Metal Research R. Yang: IMR is a leading center of materials research in China, especially in the field of high performance structural materials. IMR researchers contributed significantly to gaining fundamental understanding of materials science as well as meeting strategic demand of critical materials technology of China. With a great history of 64 years, IMR has created conditions favorable for research and innovation and encouraged technology transfer to industry. IMR is located in the cultural district of Shenyang, the largest metropolitan city in Northeastern China, and its employees enjoy excellent cultural life and leisure after work. Open in new tabDownload slide Jian Zhang: Director of Superalloys Division Zhang: The R&D of superalloys is an important research direction since the establishment of IMR and enjoys a great success in the past 60 years. IMR has provided an excellent platform for this research. Rapid and significant progress has been made in the past decade. The goals of research at IMR to meet the national demands keep us motivated and proud as researchers in IMR. IMR is located at Shenyang, which is an old industrial city in China. It is expected that the development of the Shengyang city can further promote the development of IMR. Open in new tabDownload slide Ke Yang: Director of Specialized Materials and Devices Division K. Yang: I like the environment of our institute with nice facilities, broad disciplines, academic freedoms, active international exchanges, and so on. I love to work at IMR. NSR: What attracted you most to work in the center? R. Yang: A tradition and culture of innovation, created by the founders of the institute, that encourage exchange of ideas between people in different fields and that encourage the development of technology based on fundamental understanding of scientific principles. Zhang: There are few-research institutes similar to IMR that are able to perform insight researches on superalloys, ranging from atomic scale characterization to complex manufacturing technologies in modern aerospace engineering. The 60-years’ accumulation and excellent research platform here allow us to do world-class fundamental research, solving the bottle-neck problems in the development of materials and technique and gaining recognized reputations. K. Yang: The institute has a high reputation in materials research and I can work on what I am interested in by leading a big team. NSR: Your proudest/greatest achievement thus far? R. Yang: I personally work in the field of aerospace materials and we have developed technologies that not only serve Chinese industries but also attract world leading companies like Rolls-Royce. Zhang: With ten years’ effort, we have designed the equipment and solve key technical problems in the field, realizing the practical application of high temperature gradient directional solidification technique. The directional and single crystal blades have been supplied for commercial applications. K. Yang: I am working on novel metallic biomaterials and am developing a new concept that metallic biomaterials can be offered certain biofunctions, which will increase the application values for the medical metal devices. This idea was first developed in the world and has been proved by many experimental results. NSR: Innovation potential of the institution? R. Yang: We have a long tradition of innovation and we believe this tradition will be continued. Zhang: IMR is a leading institute in materials science and engineering in China, focusing on the demands of the country as well as the frontier of science and technology. The great research platform and talents at the institute coupled with the national demands makes IMR show a great potential for the future development. K. Yang: This institute has an impressive history and a galaxy of talents with great innovation capability. I believe that more innovative achievements will be realized with greater influence if the researches in the institute are more focused with the top-level design and integration of powers. NSR: What is the prospect of the institution in the future? R. Yang: Materials are the input to manufacturing. Materials innovation, the central task of IMR, is of crucial importance to the success of strategic plans such as Made in China 2025. No doubt IMR will continue to play a key role in helping Chinese industries in their efforts to uplift the quality of their products. Materials development requires innovations in both science and technology, and research conducted at IMR will contribute to making China and indeed, the world, better and greener. Zhang: The research and design for structural metallic materials in developed countries are relatively mature and their main focus now is the reduction of cost as well as the technical optimization. Our country has now undergone the transfer from mass production and application of low-end materials to the development and application of high-end materials. Therefore, the research activities at IMR will continue to be one of the most vigorous research fields in China in the next 10 to 20 years. The research and application of advanced structural metallic materials are mostly distributed in the industrial departments in the world and relevant fundamental studies are less investigated. IMR has the whole material design and development chain, making it continue to play an important role in the materials research filed in the world, with greater influence in the field. K. Yang: I am sure that the institute will well keep going in the future through our efforts, though there exist many challenges. If the institute is able to develop in accordance with the state goals and requirements, it will still have great influence in the related field as before. TALENT RECRUITMENT AND CULTIVATION FOR YOUNG SCIENTISTS Besides the excellent research achievements that have been obtained, IMR has continually sought to build a world-class and multidisciplinary team by attracting and training outstanding research scientists, as an important part of the long-term development strategy at IMR. Currently, IMR has a well-established research team, including the members from CAS and CAE. In order for the corresponding competence to be strengthened in the research of materials science and engineering, IMR always emphasizes innovative policies by attracting outstanding research scientists to join the team and training and assisting staff members to develop a successful career. IMR provides room for the growth of young researchers and special policies has been offered to young staff, aiming to assist them become leading scientists in the future. IMR has created a new type of position, called Project-oriented Professor, for outstanding young researchers who are younger than 40, allowing them to perform excellent research work. In addition, the following four actions have been established to support the young researchers at IMR. ▪ Actions to support the young researchers ▪ Research Center of Young Scholars is established to encourage and support young researchers to independently perform investigations based on their own interests. ▪ The Young Staff Club seeks to strengthen exchanges and cooperation among young researchers. The activities include academic symposia, interest groups, and visits to selected industrial partners, with the purpose of young staff members nurturing and mutual collaborations promotion. ▪ A series of lectures for young scientists is regularly organized to build a platform to promote academic exchanges and collaborations. ▪ An Innovation Fund is allocated to support projects led by young researchers according to their own research interests and enhance collaborations among various divisions. All these efforts have led IMR to become an institute attractive for top scientists, which could enhance the corresponding success in the field of materials science and engineering. ACADEMIC LEADERS Open in new tabDownload slide En-Hou Han En-Hou Han, Professor, Environmental Corrosion Research Center & National Engineering Center for Corrosion Control, IMR Prof. En-Hou Han's research has focused on the understanding of corrosion mechanism, the development of corrosion protection techniques and the assessment of lifetime and safety for engineering structures due to materials degradation. His group investigated corrosion and cracking mechanism of nickel based alloy, stainless steel and low alloy steel for nuclear power plant and nuclear waste disposal and recommended the prediction method for real industry. They invented nano-composite coatings and nano-composite plating techniques which were applied in various industries such as automobile, electric transmission line, bridges & aircraft. He proposed new methodologies to predict the service lifetime which were used in aging aircraft and oil and gas pipelines. Open in new tabDownload slide Xin Jiang Xin Jiang, Professor, Functional Films and Interfaces Division, IMR Prof. Xin Jiang has established the Functional Films and Interfaces Division at IMR in 2011, based on the “1000 plan” program. The core objective of his research group focuses on the need for clean energy and a clean environment. Intelligent fabrication of various functional films and nanostructures has been achieved by using different technologies, with a particular interest in the rational synthesis of functional films and nanomaterials, interface engineering, surface modification and functionalization, and the exploration of their promising applications in industry. Open in new tabDownload slide Yi Li Yi Li, Professor, Non-equilibrium Metallic Materials Division, IMR Prof. Yi Li obtained the PhD degree from the University of Sheffield in 1990. He was appointed as a faculty member at National University of Singapore from 1992 and was promoted to full professor there in 2008. Now he is the “1000 talent” expert and the director of Non-equilibrium Metallic Materials Division at IMR. His research interest focuses on the analysis and control of the microstructure for new non-equilibrium materials (often alloys), which supplements knowledge of microstructure-property relationships and is essential for the design of new materials with high performance beyond present limitations. Open in new tabDownload slide Xiu-Liang Ma Xiu-Liang Ma, Professor, Division of Solids Atomic Imaging, IMR Xiuliang Ma has devoted his scientific career to exploring the atomic-scale information of materials. His group is focused on transmission electron microscopy of high-performance metallic materials and advanced functional materials. By engineering strain at the nanoscale, recently they have grown PbTiO3/SrTiO3 multi-layer films on a GdScO3 substrate, and by using aberration-corrected scanning transmission electron microscopy, they observe not only the atomic morphology of the flux-closure quadrant but also a periodic array of flux-closures in ferroelectric PbTiO3 films. This study provides a new similarity between ferroelectric and ferromagnet, and extends the potential of employing epitaxial strain for modulating ferroelectric domain patterns. Open in new tabDownload slide Zhidong Zhang Zhidong Zhang, Professor, Magnetism and Magnetic Materials Division, IMR Zhidong Zhang has devoted in the research of permanent magnetic films, magnetic nanocapules, topological spin textures in magnetic materials, and condensed matter physics theories. His group succeeded in preparation of both isotropic and anisotropic nanocomposited multilayered magnets with high performance of magnetic properties. They have invented several techniques to synthesize novel types of magnetic nanocapsules with core-shell structures exhibiting good performance for microwave absorption, catalysis, etc. Recently, he discovered the existence of magnetic skyrmions in nanostructures, revealed the topological property of magnetic domains and characterized the topological contribution to physical properties of a magnet. © The Author(s) 2017. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is properly cited. for commercial re-use, please contact journals.permissions@oup.com © The Author(s) 2017. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
TI - Institute of Metal Research, Chinese Academy of Sciences: aiming to achieve breakthroughs in the development of materials
JF - National Science Review
DO - 10.1093/nsr/nwx049
DA - 2017-03-01
UR - https://www.deepdyve.com/lp/oxford-university-press/institute-of-metal-research-chinese-academy-of-sciences-aiming-to-8aZnrfkITJ
SP - 269
EP - 282
VL - 4
IS - 2
DP - DeepDyve
ER -