The properties of stainless steel 17-4PH produced by a low cost additive manufacturing technique, the Marforged MetalX

The lower capital and running cost of the Markforged Metal X™ platform, in comparison to competing metal additive manufacturing systems, makes it a highly attractive proposition for a number of industries. The unusual, print then sinter, process also has the potential to avoid many of the metallurgy issues that can arise using more typical additive manufacturing, which relies on melting to bind the material. However, the mechanical properties of the material produced must be well understood. In this paper, the properties of 17-4PH stainless steel samples produced by the Metal X™ are documented following a systematic testing program, involving standard mechanical testing as well as materials characterisation techniques. Significant differences were observed between samples tested in differing orientations. This is thought to be due to the deposition process used to deposit the material prior to sintering. This results in voids and surface stress concentrations which reduce the strength of the material. Heat treatments and surface machining were both found to improve the tensile properties of the materials