High-Pressure XRD Study of Ti-3Al-2.5V Titanium Alloy: Intermediate Transition Pressure and Composition Trends in Ti-Al-V Alloys

TL;DR

This study investigates how alloy composition affects high-pressure phase transitions in Ti-Al-V alloys using X-ray diffraction, revealing systematic trends in transition pressure independent of elastic properties.

Contribution

It provides new insights into the composition-dependent phase stability and transition pressures in Ti-Al-V alloys under high pressure.

Findings

Transition pressure in Ti-3Al-2.5V occurs at 17-19 GPa.

Transition pressure increases systematically with higher Al and V content.

Bulk modulus remains nearly unchanged across different alloy compositions.

Abstract

High-pressure X-ray diffraction experiments were performed on Ti-Al-V alloys to investigate the effect of composition on structural stability, focusing on Ti-3Al-2.5V and comparing with pure Titanium and Ti-6Al-4V. Measurements using different pressure-transmitting media show a phase transition in Ti-3Al-2.5V at 17-19 GPa, intermediate between pure Ti (5-10 GPa) and Ti-6Al-4V (~30 GPa). Despite variations arising from the choice of pressure medium, the transition pressure shows a clear and systematic increase with higher Al and V content. Equation-of-state analysis indicates that the bulk modulus remains nearly unchanged across compositions. This suggests a decoupling between elastic properties and phase stability, with alloying primarily affecting the transition pressure rather than compressibility. These results highlight the role of composition in tuning high-pressure phase transformations in Ti-Al-V based alloys.