Mechanical alloying and thermal analysis of Ta–Ti alloys

Abstract

Tantalum–titanium alloys have widespread potential in biomedical applications due to their superior biocompatibility, favorable mechanical properties, high corrosion resistance, and ability to exhibit shape memory behavior. However, this system is plagued by processing difficulties due to significant differences in melting temperatures, specific weights, and vapor pressures of Ta and Ti. In the present study, mechanical alloying (MA) using high‐energy ball milling of Ti–xTa (where x = 50, 60, 70, and 85 wt%) was investigated. The alloyed powders were characterized by X-ray diffraction, electron microscopy (SEM and TEM), and differential scanning calorimetry. It was established that α-Ti (hcp) gradually dissolves into α-Ta (bcc), with the alloyed particles becoming chemically homogeneous as a bcc structure. This structure corresponds to a meta-stable phase and should decompose to yield two solid solutions, Ti-rich hcp and Ta-rich bcc. To overcome this thermodynamic preference, MA-generated Ta–Ti bcc solid solution powders possess relatively high internal strain energy.