Ti-Ta Alloys Employed as High Temperature Shape Memory Alloys: Effects of Thermo-mechanical Process on Microstructure and Wear Behaviour

Zuheir Talib Khulief and Moqdad J. Dakhil

This work was mainly aimed to investigate the effects of thermo-mechanical process on microstructure and wear properties of Ti70-Ta30alloy fabricated in this work, which are candidate as high temperature shape memory alloys. Alloy was studied under different conditions as casting (CA), after homogenisation (H), after cold rolling (CR), after hot rolling (HR) and after hot rolling followed by cold rolling (HR + CR). The dry wear properties were studies under all above conditions. In this work alloys composition are given in atomic percent (at %), unless stated otherwise. The alloy was characterized before the wear test using X- ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Friction coefficient, wear track parameters (length, width, depth, volume loss, specific wear rate), surface roughness parameters (Ra, Rp, Rq, Rt, Rv) under different conditions of the wear tests measured and calculated. The microstructural analysis illustrated that the alloys consisted of two phasesαʺ orthorhombic martensitic inside an equiaxed β phase microstructure. The results illustrate that the coefficient of friction is unaffected by the thermo-mechanical process, all conditions illustrate average values (0.29 – 0.33). The wear mechanism was abrasive ploughing. The alloy as casting was more susceptible to wear compare to other conditions, while the alloy after hot and cold rolling (HR + CR) illustrates better wear resistance.

Volume 12 | 04-Special Issue

Pages: 371-381

DOI: 10.5373/JARDCS/V12SP4/20201501