Development of porous TiAl based intermetallics by powder metallurgical route

초록

Various types of porous structure were developed in the TiAl based intermetallics by using a reactive sintering process and the compressive properties for the reactive-sintered porous materials were evaluated in this study. The reactive sintering process involved an extrusion of powder mixtures consisting of elemental titanium and aluminum alloy powders, and reactive sintering of the extruded powder mixtures. Since pores were developed within the TiAl based matrix by diffusion phenomena in the course of reactive sintering stage, the pore structure in the reactive-sintered material could be controlled by the structural morphology of extruded material. As we expected, spherical or unidirectional pores were successfully developed within the TiAl based intermetallics by controlling extrusion condition. The porosity and aspect ratio of the pores within the reactive-sintered TiAl based intermetallics were measured and used to discuss on mechanical properties of these materials. It was revealed that the reactive-sintered material containing unidirectional pores shows higher yield strength compared to the reactive-sintered material having spherical pores.