Influence of Hot-Rolling Deformation on Microstructure, Crystalline Orientation, and Texture Evolution of the Ti6Al4V-5Cu Alloy

The influence of hot-deformation on the microstructure, crystalline orientation, and texture evolution of Ti6Al4V-5Cu, an antibacterial (alpha+beta) titanium alloy, was investigated. The alloy was deformed using a hot rolling process in 15%, 58%, and 73% thickness reduction ratios. It was found that the basal (A) over right arrow and pyramidal (C) over right arrow+(A) over right arrow type slip planes could be activated in the a phase, which dominated the deformation behavior of Ti6Al4V-5Cu alloy. Under various deformation conditions, the alloy revealed different microstructure features. On the 15% hot rolled alloy, the deformation was performed by the breakdown of prior beta grain boundaries (GB(beta)), which was attributed to the formation of coarse alpha grains, rotated nearly 45 degrees with respect to the transversal and rolling directions. The presence of different sub-structure geometries made the interior grain size distribution heterogeneous. On the 58% hot rolled alloy, Ti2Cu intermetallic compound was found at the alpha/beta interface. High-resolution transmission electron microscopy investigation showed the occurrence of grain rotation in different crystallographic directions. At room temperature, the percentage elongation (El) of the alloy reached 23.15% on the 58% hot rolled sample. On the 73% deformed alloy, refined and randomly oriented characteristics of grains were obtained due to higher thickness reduction, which resulted from the segregation of very fine granules. The influence of grain rotation during a hot rolling process revealed that the alpha/beta texture fiber separation angle to maintain the Burger orientation relationship of {0001}(alpha)//{110}(beta) planes decreased with increase of the thickness reduction ratio when Ti6Al4V-5Cu alloy was deformed by a hot rolling mechanism. Activation of tensile {10 (1) over bar 2} < 10 <(11)over bar> and compressive {11 (2) over bar 2} < 11 <(23)over bar> twins on the deformation of the alloy was also studied.