TIAL-BASE HEAT RESISTANT ALLOY HAVING COLD FRACTURE TOUGHNESS, HIGH TEMPERATURE OXIDATION RESISTANCE AND HIGH TEMPERATURE STRENGTH

摘要

PURPOSE:To obtain the title heat-resistant alloy by specifying the compsn. constituted of Al, Nb, Si, Zr and Ti. CONSTITUTION:The TiAl-base heat resistant alloy having excellent cold fracture toughness, high temp. oxidation resistance and high temp. strength can be obtd. by forming it with the compsn. constituted of, by weight, 29 to 35% Al, 0.5 to 20% Nb, 0.1 to 1.8% Si and/or 0.3 to 5.5% Zr and the balance Ti with inevitable impurities and regulatively contg. about =0.6% O, about =1% N and about 0.05% H as the above impurities. The above alloy preferably has about =13MP am0.5 fold fracture toughness value, has the creep rupture strength for 100hr at 820 deg.C higher than that of the conventional TiAl-base alloy and has about =0.1mm quantity of decrease in plate thickness per one face after heated to about 900 deg.C for about 500hr in the air.