| TiAl intermetallic compounds based on γ-phase were consolidated by hot extruding the mixture of elemental powders of Ti, Al and other additives. The effects of alloying elements and heat treatment on tensile ductility were studied. During hot extrusion, the powder mixture was fully densified and the added B, Cr, Mn, Mo or Nb was completely dissolved into γ phase. The alloys heat-treated at 1250℃ followed by 950℃ after hot extrusion consisted of equiaxed γ and lamellar γ+α₂ phases. Addition of Mn or Mo refined the grain size and improved the room temperature tensile elongation up to about 4%. The improvement in tensile ductility of the tested alloys was attributed to fine grain size by added elements and proper control of the amount of α₂(about 20vol.%). |
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