Effect of deformation temperature on mechanical properties, microstructure, and springback of Ti-6Al-4V sheets

Abstract

Ti-6Al-4V titanium alloy is applied in various industrial applications such as aerospace, jet engine, and automotive industries due to its strength-to-weight ratio and excellent high-temperature properties. For these demanding applications, the formability of the material and the effect of forming parameters on the final mechanical properties are of great importance. In this study, the springback behavior of hot-formed 1 mm sheet Ti-6Al-4V alloy was investigated related to the deformation temperature ranging from 350 to 950 degrees C. After the hot forming, the springback angles of the U profile were examined and associated with the mechanical properties and the microstructural evolution. The microstructure changing mechanisms were mapped at each temperature of deformed sheets with the help of optical microscopy. As a result, it was observed that important microstructural changes have occurred, such as recrystallization, grain growth, and phase transformations, which themselves greatly influence the springback angle and the mechanical properties. The formability of the Ti-6Al-4V sheet material was found to be strongly dependent on the applied process temperatures and the activated microstructural deformation mechanisms. Hot forming at 850 degrees C leads to the lowest springback angle, but after the hot-forming, pronounced softening of the material occurs due to the recrystallization.