Effect of Solution-Treated Temperature on Microstructure in TiNixCu12 (x = 39, 40 at %) Alloys

Abstract

Ti–xNi–12Cu (at%) (x = 39, 40) alloys were prepared and then their transformation behavior and microstructures were investigated after solution treatment at various temperatures by means of scanning electron microscopy, energy dispersive X-ray spectroscopy, and differential scanning calorimetry. Matrix (B2), Ti2 (Ni, Cu) and Ti(Ni, Cu)2 phases were observed in all specimens except the TiNi39Cu12 alloy solution treated at 1373 K in which matrix (B2) and Ti2 (Ni, Cu) were observed. Volume fraction of Ti(Ni, Cu)2 phase decreased with increasing solution treatment temperature. All specimens showed the B2–B19 martensitic transformation behavior. Transformation temperatures and hysteresis decreased with increasing solution treatment temperature, which was ascribed to the decrease in the volume fraction of Ti(Ni, Cu)2 phase resulting in the increase in Ni content of matrix.