Presidential Young Investigator Award: Metastable Phase Formation in Intermetallic Systems

该项目涉及有可能形成连续固溶体的C.sC1(B.2)化合物组合的研究。最初的研究将集中在由离子束混合产生的REAL和NiAl的组合上。Ni和Re在Ni亚晶格上可以自由取代，有可能发生调幅分解。将根据由两个B-2结构定义的准二元相图对合金进行热力学和动力学研究。固溶体合金的分解将在分析电子显微镜中使用原位热阶段进行。此外，预计将在B.2结构中形成反相区，如果可行，将使用高分辨率显微镜研究这些特征。还将进行现场变形研究，以期观察B.2结构的工作滑动系统的变化。对于具有良好滑移行为的合金，将探索快速凝固工艺。其他研究将集中在Heusler.型合金上。

The project deals with a study on combinations of C.sC1 (B.2) compounds which have potential for the formation of continuous solid solutions. Initial studies will focus on a combination of ReAl and NiAl which will be produced by Ion.beam mixing. Ni and Re should substitute freely on the Ni sub.lattice with the possibility of a spinodal decomposition. Thermodynamic and kinetic studies will be performed on alloys based on the quasi-binary phase diagram defined by the two B-2 structures. Decomposition of the solid solution alloys will be performed using a hot stage in situ in an analytical transmission electron microscope. In addition, anti.phase domains are expected to form in the B.2 structure and these features will be studied, if feasible, by high resolution microscopy. In situ deformation studies will also be performed with expectation of observing a change in the operating slip system of the B.2 structures. Rapid solidification processing will be explored for alloys exhibiting favorable slip behavior. Additional studies will focus on the Heusler.type alloys.