High-speed nanoindentation mapping of a near-alpha titanium alloy made by additive manufacturing

Abstract

Titanium alloys are widely used in additive manufacturing, but their complex microstructures and related micromechanical properties have not been fully explored. Here, we employ high-speed nanoindentation mapping, electron probe microanalysis, and electron backscatter diffraction to characterize as-deposited and heat-treated Ti–6Al–2Zr–Mo–V alloys. Our results show the correlations between mechanical contrasts (hardness and elastic modulus) and phase contrasts (α and β). The hardness and elastic modulus of the α and β phases are increased due to the element redistribution after annealing (Al diffuses from β to α; Mo and V diffuse from α to β). We use a K-means clustering algorithm to analyze the nanoindentation dataset and correlate the mechanical property maps to the distribution of α and β phases. Our study employs the emerging high-speed nanoindentation mapping to give a better understanding of the microstructure–mechanical property relationship of additive manufactured multiphase alloys across length scales.