Selective electron beam melting (EBM) is a layer-by-layer additive manufacturing technique that shows great promise for fabrication of medical devices and aerospace components. Before its potential can be fully realized, however, a deeper understanding of processing-microstructure-properties relationships is necessary. Titanium alloy (Ti-6Al-4V) samples were built in a newly developed, unique geometry to allow accurate investigation of the following intra-build processing parameters: energy input, orientation, and location. Microstructure evaluation (qualitative prior-β grain size, quantitative α lath thickness), tensile testing, and Vickers microhardness was performed for each sample. For a wide range of energy input (speed factor 30-40), small differences in mechanical properties (2 % change ultimate tensile strength (UTS), 3 % change yield strength (YS)) were measured. Vertically built samples were found to have no difference in UTS or YS compared to horizontally built samples, but the % EL was 30 % lower. Orientation within the x-y plane as well as location were found to have less than 3% effect on mechanical properties, and it is possible a second order effect of thermal mass contributed to these results.
Citation: Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing
Pub Type: Journals
Electron beam melting, titanium alloy, tensile, microhardness, microstructure