Recrystallization behavior of boron-modified commercial-purity titanium during hot deformation

A comparative investigation of the recrystallization behavior of as-cast commercial-purity (CP) titanium VT1-0 with addition of 0.2 wt % boron and of unalloyed CP titanium in the hot-rolled and as-cast states has been performed. The introduction of boron leads to the formation of uniformly distributed short filaments and particles of titanium monoboride (TiB), which stimulates a substantial refinement of the cast structure. The recrystallization behavior of the alloys was studied after deformation by compression at T = 900-600°C using the EBSD analysis. It has been established that the kinetics of the recrystallization of the as-cast VT1-0-0.2B alloy is substantially accelerated compared with that of the unalloyed VT1-0 alloy due to the presence of borides. The recrystallization behavior of the VT1-0 alloy with the initial hot-rolled structure and of the VT1-0-0.2B alloy with the as-cast structure proved to be approximately similar. Based on the investigations performed, recommendations have been made that should facilitate (and reduce the cost of) the production of fine-grained and ultrafine-grained semi-finished items of CP titanium.