抄録
The Ti-6Al-4V alloy is a very attractive material for the fastener bolt of an aircraft because of its excellent combination of specific strength and corrosion resistance. However, poor workability and severe galling between work-piece and die material make it difficult to produce. The aim of the present work is to enhance the hot formability of the Ti-6Al-4V bolt. Multiple forgings were simulated using FE code to determine optimum process parameters including workpiece temperature, strain rate, and damage value. Various thermal oxidation treatments were investigated in order to prevent galling and increase the hot-workability. After the oxidation treatment, hot forging was conducted and the microstructure of forged specimens was investigated. Among the various heat treatments, holding at 750°C for 2 h provides the most homogeneous microstructure and a sufficiently low galling phenomenon after forging. Mass-gain versus time curves for isothermal oxidation were obtained in order to analyze the oxidation behavior.
