Metal Additive Manufacturing Conference 2019

Metal-Powder Bed Fusion (PBF) is an Additive Manufacturing technique, capable of producing near fully dense metal parts with good properties and complex geometries. Especially in the case of the manufacture of titanium alloy parts by this process, a post-processing heat treatment is required, however a number of different ones are known. In this project we manufactured parts from Ti6Al4V alloy powder, using an EOS M290 PBF machine, then investigated the properties of parts in three different thermal conditions, as built, after a stress relief heat treatment, and after Hot Isostatic Pressing (HIP). Part properties considered include density (by helium pycnometry), tensile properties, hardness and metallurgy. Results obtained show little difference in parts before and after the stress-relief cycle, but a significant change to the mechanical properties (reduced UTS and higher elongation) and metallurgy after the hotter HIP cycle. No significant differences in density were measured between parts, however while the HIP process is intended to increase density by reducing voids, this will only be true if they are present before this process.