Precipitation and recrystallization behavior of beta titanium alloys during continuous heat treatment

Abstract

Precipitation and recrystallization behavior during the continuous heat treatment of three beta-titanium alloys with various molydenum equivalents (VT22, Ti-15-3, and TIMETAL-LCB) was established. Following solution treatment, the materials were cold deformed to various reductions and then heated at rates between 0.17 and 50 K s−1 to peak temperatures below and above the beta-transus temperature. Precipitation below the transus was most rapid for the alloy with the least amount of beta stabilizing elements (VT22) and next fastest for the most-highly-alloyed material (TIMETAL-LCB), an effect ascribed to its large iron content. The reduction level was found to have a very strong influence on the uniformity of recrystallization and the recrystallized grain size. Because of the competition between precipitation and the temperature dependence of recrystallization nucleation and growth, the heating-rate dependence of the recrystallization temperature for the beta-titanium alloys was weak.