EFFECT OF CALIBER ROLLING TEMPERATURE ON ROOM AND ELEVATED TEMPERATURE TENSILE PROPERTIES OF Ti-6Al-4V ALLOY

摘要

Ti-6Al-4V alloy was caliber rolled (CR) to 92% reduction in cross section area in the temperature range of 750-850 °C. Caliber rolling to a strain >2 resulted in grain refinement ranging from 0.53 to 1.04 μm, which led to enhancement in room temperature yield strength and tensile stregth. The work hardening rate (θ) showed higher value at the strain level of ～0.13 for CR 800 °C and 850 °C as compared to CR 750 °C material. Also, differential strain rate test was done at 850 °C, over the strain rate range of 10~(-4) to 10~(-1) s~(-1), to explore the optimum condition for superplasticity. Initial constant strain rate tensile tests at optimized strain rate of 10~(-3) s~(-1) and the test temperature of 850 °C showed the tensile elongations ranging from 530 to 560%, depending on caliber rolling temperature.