PRODUCTION OF DISPERSION-STRENGTHENED HEAT-RESISTANT SINTERED ALLOY

摘要

PURPOSE:To easily obtain the titled heat-resistant sintered alloy having improved mechanical strength and high-temp. strength by compacting the dispersion-strengthened powder which is mechanically compounded and alloyed at the Solvus temp. of a gamma' pohase or below then subjecting the powder to superplastic working and further to recrystallization annealing and heat treatment. CONSTITUTION:The dispersion-strengthened powder described above is compacted by a working method such as hot hydrostatic press, hot press or forging at the Solvus temp. of the gamma' phase or below. A preform having about =95% alloy density and =10mum average crystal grain size is thus obtd. The preform, i.e., the dispersion- strengthened alloy having the fine crystal grains is subjected to =70% superplastic working at low-stress and low-strain strength and is then subjected to the recrystallization annealing to form the coarse grains having =500mum average crystal grain size. The alloy having the increased average crystal grain size is subjected to the heat treatment and the dispersion-strengthened heat-resistant sintered alloy having the improved mechanical strength and high-temp. strength is obtd. The process for production of this invention exhibits a particularly remarkable effect with the Ni-, Co- or Fe-base oxide dispersion-strengthened ultra-heat-resistant alloys.