A micromechanical study of high temperature Ti-AI powder compaction

Process induced micro-scale evolutions can greatly influence the strength and resilience of a high temperature ceramic and intermetallic component. A micromechanical study, based on a unit cell approach, is carried out in the present work to investigate these evolutions during compaction of titanium aluminide multi-phase intermetallics at elevated temperatures. The quasi-coupled unit cell analysis can provide an avenue for investigating scalability and migratability of laboratory results to full scale productions with perturbed material compositions. Effects of various macro-scale process design considerations (e.g., tooling stiffness, spatial distribution of thermal fields) on micro-scale evolutions are investigated in detail. It has been observed that a more economic (and usually more flexible) container increases the likelihood of microcrack nucleations, while spatially non-uniform intra-particle thermal fields can be utilized to alleviate processing induced micro-cracks in the final compacted product. Possibilities for process design modifications are also discussed. © 1998 by ASME