抄録
Mechanical properties at elevated temperature of six commercial Ni-base heat-resisting alloys were investigated, and the effects of Co, Mo and Nb on mechanical properties were compared.
When compared the mechanical properties of Ni-Cr were with Ni-Cr-Co alloys, Co was found. to be effective to increase strength at high temperature and long time test, and it also increased ductility at room & elevated temperature.
Mo was found to be effective to increase strength at high temperature, but it gave effect to decrease at high and long time test. M252 which contained 10% of Mo was found to have a lower creep rupture strength above 750°C than Inco 700 which contained lower Mo, but higher Ti, Al and Co. But M252 had the highest creep ductility at high temperature.
Nb was found to be effective to increase high-temperature strength as well as Ti & Al. But its effect was not clear in short time test of tensile strength. Therefore, Inconel X-550 had the highest stress rupture strength among Ni-Cr alloys. Creep ductility was decreased remarkably by the addition of 1.2% Nb as Ni-Cr alloys which contained high Ti and Al.
