Incorporating microstructural and mechanical heterogeneity to Ti-Zr-Nb alloy by partial high-energy ball milling

Abstract

This study introduced a novel method for incorporating microstructural and mechanical heterogeneity into Ti-Zr-Nb alloy to improve its strength without significantly affecting the elastic modulus. Ti-Zr-Nb alloy powder was milled at different ball-milling energies using a planetary ball mill, mixed with parent pristine powder in equal weight fractions using a horizontal ball mill, and sintered using spark plasma sintering. The resulting bimodal-like microstructure showed an increase in tensile yield strength (up to 410 MPa) without significant changes in the elastic modulus (<6 GPa). Milling followed by sintering caused grain refinement and precipitation in the relevant zones of the sintered samples, resulting in a heterogeneous structure due to the unique spread of alpha-precipitates. The strength of the heterogeneity-incorporated alloys was improved as a function of milling while maintaining high plasticity and a low elastic modulus.