Influence of anisotropy properties and structural inhomogeneity on elasticity and fracture of titanium alloys produced by electron-beam melting

The paper studies the influence of anisotropy of properties and structural inhomogeneity on hardness and mechanical properties of titanium Ti-4Al-3 V alloy produced by wire-feed electron-beam additive manufacturing. Tensile and compressive strength testing of the alloy specimens determines its elastic modulus and strength properties at different points. VIC-3D digital optical system is used to study the mechanical properties of the material under stress. The fractography analysis explains the observed behavior of the material under different loading. It is shown that after the tension, specimens possess close values of mechanical properties in various directions, except for their bottom, where the structure changes due to partial mixing of deposited and substrate materials. Just the material plasticity changes notably in the volume, which is the highest in the growth direction. This is probably stipulated by the low number of barriers to the dislocation motion during tension. In compressive strength testing, constrained conditions for the dislocation motion in columnar grains provide a higher strength for specimens cut in the growth direction, than for those cut in the printing direction. All this will allow us to more accurately choose the hardening technology of such materials and probably recommend methods of fabricating small-sized parts.