Effect of build thickness and geometry on quasi-static and fatigue behavior of Ti-6Al-4V produced by Electron Beam Melting

Abstract

The geometry and material properties of additively manufactured (AM) parts are closely related in a way that any alteration in geometry of the part will change the underlying manufacturing strategy. This in turn, affects the microstructure and consequently, the mechanical behavior of material. This paper aims to evaluate the effect of the AM part’s thickness and geometry on microstructure, surface roughness, and mechanical properties under quasi-static and fatigue loading conditions by performing experimental tests. A series of Ti-6Al-4V specimens with three different thicknesses and two different geometries were fabricated using electron beam melting (EBM). The results of microstructural analyses revealed that specimens with lower build thickness experience finer grain size, higher microhardness, and lower elongation at failure. Although the microstructure of the produced parts was strongly affected by the build thickness, different surface to volume ratios eliminated the effect of microstructural differences and governed the fatigue properties of the parts. The size effect on the microstructural features, geometrical appearance, mechanical properties of the AM parts should be considered for the design and failure analysis of complex structures.