Optimization of formability parameters of alpha–beta-processed titanium alloy at elevated temperature

Abstract

A material’s inherent ability of strain distribution decides forming limits and affects the overall formability. In the present work, aero space grade titanium alloy – Titan 31 developed by MIDHANI India is selected. The material is hot rolled under alpha–beta-rolling process and heat treated at different temperatures and subjected to various cooling rates in the alpha plus beta regime to obtain a fine equiaxed alpha–beta microstructure that ensures high formability . Taguchi’s design of experiments approach is used to optimize the processing parameters (temperature, crosshead speed and angle-to-rolling direction specimen tested) to maximize formability depending on intrinsic material properties. Percentage contributions of these parameters towards maximizing the formability are also determined using analysis of variance. The optimal combination of parameters is evaluated as a temperature of 998 K, a crosshead speed of 1.25 × 10⁻⁵m/sec and an angle of testing the specimen from rolling direction 45°, among all the parameters selected in the study.