Abstract
Two types of commercial Ti alloy powders (Ti-6AI-4V and Ti-6A1-2Sn-4Zr-6Mo, <500 μmφ) made by a rotating electrode process (REP) have been resistance-sintered in air. The relation between physical and mechanical properties of sintered specimens and their resistance-sintering conditions have been studied. The effects of various heat treatments on the properties of resistance-sintered specimens have been also examined.
These powders in a die insulated by mica were resistance-sintered under a pressure (1.2 t/cm2). The condition of resistance-sintering was as follows: electric current; 7.6-15 kA, voltage; 2.5-4.7 V, time; 0.6-2.0 sec (30-100 C, C; cycles) and power input; 45-190 kVAC/g (1 kVAC=9.8 J).
By the resistance-sintering with a power input higher than 140 kVAC/g, specimens having high density-ratio (>98% theoretical) and high tensile strength could be obtained (Ti-6A1-4C; 120 kg/mm2, Ti-6A1-2Sn-4Zr-6Mo; 100 kg/mm2). Resistance-sintered specimens of both alloys were strengthened by the solu-tion-treatment and the aging (STA) heat treatment (tensile strength-130 kg/mm2). Tensile strength of resistance-sintered Ti alloys was almost comparable to that of those water-quenched.
