Strengthening/Weakening Action of Zr on Stabilizers of Ti Alloys and Its Effect on Phase Transition

Phase transition is a basic key factor to adjust and control the microstructure and properties of metal and alloys. Alloying elements have great effects on the phase transition. This work investigated the effect of Zr addition on the phase transition of Ti and Ti alloys with various stabilizers via thermodynamic simulation using the CALPHAD (Calculation of Phase Diagrams) method and verified by previous experimental results. Al, Mo, and Cu were selected as the representative of the typical alpha-, isomorphous beta- and eutectoid beta-stabilizer, respectively. The addition of Zr into Ti alloys with various stabilizers not only shows its decreasing effect on phase transition temperatures but also affects the effectiveness of other stabilizers. The addition of Zr would weaken the stabilizing effect of alpha-stabilizers but enhance the effectiveness of beta-stabilizers. Furthermore, alloying content correlation of alpha <-> beta phase transition temperatures of TiZr, TiAlZr, TiMoZr, and TiCuZr systems was obtained. This finding could help to understand the phase transition of Ti alloys, guide the design and preparation of new Ti alloys with desired phase constitution and properties, and deepen the alloying theory as well.

Automated summary

This study investigated the effect of Zr addition on the phase transition of Ti and Ti alloys with various stabilizers through thermodynamic simulation and experimental verification. Zr addition decreases phase transition temperatures and affects the effectiveness of other stabilizers. This finding is important for guiding the design of new Ti alloys and deepening alloying theory.