Simulation of β-stabilised γ-TiAl Alloy Rolling and Its Defects Analyses

Abstract

To overcome the poor ductility of this two-phase (γ+γ/α2) material, novel β-solidifying multi-phase γ-TiAl based alloys were developed to improve the hot workability. In order to study the plastic deformation characteristics of β-stabilised γ-TiAl alloy and find out the feasibility of using computer simulation to analyse the hot deformation process, the rolling process of TiAl billet was simulated by means of DEFORM 3D. It is concluded that (1) the changes of the temperatures, stresses and strains at the different regions of the billet were simulated during the entire rolling process, (2) based on the stress and strain distributions of the rolled billet, the forming defects analyse was proceeded and it is concluded that some rolling defects or flaw occur near the head surface or around the side edge during the plastic deformation process. During the rolling process, rolling force decreased with the elevation of rolling temperature and the reduction of rolling rate and pass reduction. Since the cooling rate of the sheet edges is faster with lower temperature, it is easy to generate stress concentrated in edge region during the deformation process. The greater the reduction is and the greater the damage is. In summary, in order to ensure the success of TiAl based alloy sheet rolling, it should be used at higher temperatures, lower rolling reduction rate and slower rolling rate.