Control of micro-structure and phase interface for concurrent design of multi-functional materials.

研究了组织、相界面和晶界特征的控制因素，实现了合金和金属间化合物强度、塑性和功能性能的并行设计。对于有望成为新型轻质耐火材料候选材料的富铝TiAl化合物，研究了L10结构的γ基体中Al 5 Ti 3析出相的形貌和取向关系，确定了相变过程中反相界的择优选择。还确定了具有11b和C40结构的难熔金属硅化物的变体选择，并通过控制变体和双相结构来执行这些硅化物的机械性能。本文研究了晶界特征、外加应力和预应变对含控制倾斜、扭曲和随机晶界的Fe-Ni双晶马氏体相变的影响。为了改善FeAl、NiAl等B2结构金属间化合物的晶界脆化，控制了晶界析出的金属间化合物薄膜相，显著提高了其力学性能。通过控制含晶界特征和织构的显微组织，也可提高其功能性能。通过控制晶界特征和织构，获得了Fe-Pd形状记忆合金的巨磁致伸缩。一个适当的热机械过程中开发，以获得重合晶界和等轴晶粒。

Control factors of micros-structure, phase interface and grain boundary character were examined to carry out the concurrent design of strength, ductility and functional properties of alloys and intermetallic compounds. For Al-rich TiAl compound which is expected as a candidate for new light weight refractory materials, morphology and orientation relationship of Al5Ti3 precipitates in γ matrix with the L10 structure were examined and the preferential selection of anti-phase boundaries during phase transformation was determined. Variant selection of refractory metal silicides with the 11b and C40 structures were also determined and the mechanical properties of these silicides were performed by controlling the variants and duplex structure. Effects of grain boundary character, applied stress and pre-strais on the martensitic transformation was examined using Fe-Ni bicrystals containing controlled tilt, twist or random boundary. To improve brain boundary embrittlement of intermetallic compounds with B2 structure such as FeAl and NiAl, dutile intermetallic thin film phase precipitates at grain boundary was controlled and remarkable improvement of their mechanical properties was obtained. Functional properties were also improved by control the microstructure containing grain boundary character and texture. A gigantic magnetostriction in Fe-Pd shape memory alloy was obtained by controlling the grain boundary character and texture. An appropriate thermomechanical process was developed to receive coincidence grain boundaries and equiaxial grains.