MA-PS(プラズマ加圧焼結)法による傾斜機能材料の創製

概要

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A novel P/M processing is developed, which consists of plasma sintering with the aid of an applied stress and a temperature gradient and a high quality powder production of amorphous TiAI by mechanical alloying, for the fabrication of a functionally gradient materials(FGM) of zirconia-titanium aluminide system. Our processing makes it possible to obtain a FGM of FSZ/TiAl without a visible crack-like discontinuity throughout an overall cross section with a short-time sintering of 300 s and a relatively low applied stress ranging from 29 to 59 MPa. Plasma sintering leads to a full dense compaction, mainly via viscous flow in amorphous TiAl matrix, in layers between TiAI and 50%-TiAl/FSZ, and a relatively high hardness of 807 Hv for 7-phase TiAl including a small amount. of α<SUB>2</SUB>(Ti<SUB>3</SUB>Al) and at the maximum, 1016 Hv at 25 %FSZ/TiAl. These higher levels are explained by strengthening mechanisms of nano-meter scaled grain and FSZ particle dispersion respectively. Two-step plasma sintering with a greater temperature gradient realizes the enhanced hardness and relative density of FSZ-rich layers.
社団法人粉体粉末冶金協会の論文