A Self-Consistent Approach for Modeling the Flow Behavior of the Alpha and Beta Phases in Ti-6Al-4V

Abstract

The flow behavior of the alpha and beta phases in Ti-6Al-4V was interpreted in the context of a self-consistent modeling formalism. For this purpose, high-temperature compression tests were conducted at various temperatures for a single-phase alpha alloy (Ti-7Al-1.5V), a variety of near-beta alloys, and the two-phase alloy Ti-6Al-4V, each with an equiaxed microstructure. The flow behavior of the alpha phase in Ti-6Al-4V was deduced from the experimental results of the single-phase alpha alloy. The flow behavior of the beta phase, which was predicted by using the self-consistent approach and the measured flow behaviors of Ti-6Al-4V and Ti-7Al-1.5V, showed good agreement with direct measurements of the various near-beta alloys. From these results, it was shown that the strength of the alpha phase is approximately three times higher than that of the beta phase at temperatures between 1088 K and 1223 K (815 A degrees C and 950 A degrees C). It was also concluded that the relative strain rates in the two phases varies significantly with temperature. The usefulness of the approach was confirmed by comparing the predicted and measured flow stresses for other Ti-6Al-4V and near-alpha alloys.