EFFECTS OF ENVIRONMENT AND HEAT TREATMENT ON THE TENSILE AND FATIGUE PROPERTIES OF Ti‐24 at%A1‐11 at%Nb

Abstract

Ahtract-The a2 + j alloy Ti-24 at%Al-ll at%Nb was evaluated for mechanical properties in the as-received, mill annealed condition (nearly equiaxed) and in the B annealed condition (basketweave).The as-received condition had a moderately strong basal transverse 0 1~ texture which gave a higher yield strength, higher elastic modulus, and higher fatigue crack growth rate (FCGR) for loading in the transverse direction at room temperature. The j annealed material was stronger and more isotropic in both texture and properties. The fatigue crack growth rate is higher at 732°C in argon than at room temperature. A hydrogen environment results in a FCGR at 732°C comparable to or less than the FCGR in argon at 732°C for the as-received and /J annealed conditions respectively. Although the hydrogen in solution at levels as high as several thousand ppm does not embrittle at elevated temperature, embrittlement is found after cooling to room temperature.