Enhancement of fatigue resistance using the accelerated diffusion/sintering phenomenon near beta transus temperature in Ti-6Al-4V powder metallurgy alloy

摘要

Rapid sintering at the beta-transus temperature (1010 degrees C) of a titanium alloy (Ti-6Al-4V), by exploiting the accelerated self-diffusion, is shown here to yield a high density (similar to 98%), and a refined microstructure, relative to that obtained at a higher sintering temperature in powder-metallurgical processing. While saving energy and cost, this approach is shown to produce a nearly equivalent tensile stress-strain behavior, and, strikingly, a significant improvement in overall S-N (stress-life) fatigue resistance, relative to that of the alloys sintered at a relatively higher temperature. This new approach may be broadly applicable to all titanium alloys exhibiting alpha-to beta phase transformation. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.