Effect of heat treatment on tensile behaviour of Ti-6Al-5Zr-0.5Mo-0.25Si alloy

Tensile behaviour of the near a titanium alloy, Ti-6Al-5Zr-0.5Mo-0.25Si (LT26A), was investigated in (α + β) as well as β treated condition, over a wide range of temperature from RT to 823 K. It was observed that there were distinct serrations on the load-elongation curves of the a + β treated material at intermediate temperatures from 623 to 723 K. Tensile tests at 673 K over a wide range of strain rate from 0052 to 5.60 (× 10-2) s-1 showed negative strain rate sensitivity. Thus, occurrence of DSA was confirmed. It was established from the measured activation energy for DSA that it was essentially controlled by diffusion of the solid solution strengthener silicon in the matrix.