Investigation on diffusion kinetics of Ti-X binary systems at 1300–1500 °C

Abstract

The composition design of titanium alloys and some preparation processes require accurate diffusion kinetic databases. However, the current database of diffusion kinetics at high temperatures is not yet complete. In this work, the diffusion kinetics of five binary systems, Ti–Zr, Ti–Nb, Ti–Mo, Ti–Ta and Ti–W, were systematically investigated at 1300–1500 °C. The interdiffusion coefficients and impurity diffusion coefficients of the Ti-X binary systems were calculated according to the Den-Broeder and Hall methods. The results showed that the Ti–Nb, Ti–Mo, Ti–Ta and Ti–W exhibited strong concentration dependence of the diffusion coefficients at the temperature of 1300–1500 °C compared to the Ti–Zr system, which was considered as the domination of the difference in intrinsic properties between elements. Besides, the activation energies of diffusion were evaluated based on the Arrhenius relationship, where the Ti–Zr system exhibited the lowest activation energy among the five diffusion systems, followed by Ti–Nb, Ti–Mo, Ti–Ta and Ti–W systems. The diffusion kinetic data of titanium-based alloys at high temperatures were obtained in the present work, providing important references for the design, preparation and processing of new titanium alloys.

Keywords

• Diffusion couple
• Ti-based alloys
• Diffusion behavior
• Interdiffusion coefficients
• Activation energy