Fatigue properties of conventionally manufactured and micro-powder-injection-moulded 17-4PH micro-components

Abstract

Micro-powder injection moulding (μPIM) is a promising mass manufacturing technique for the microsystem technology. Because typical applications - like sensors or actuators - need to withstand serious mechanical loadings, the investigations of the mechanical properties are of vital importance. Therefore, we implemented a small-scale testing setup that enables tensile and tension-tension-fatigue testing of freestanding micro-samples. This allowed for investigating tensile and fatigue properties of conventionally produced and μPIM 17-4PH stainless-steel thin membranes. The conventionally produced samples were machined from bulk material and showed properties and lifetimes comparable with the best bulk samples. The μPIM samples showed a weaker but more ductile behaviour, due to a ferritic phase and SiO2 inclusions. But their ultimate tensile strength of up to SU = 1021 ± 48 MPa and their relative fatigue strength of ≈46% SU (R = -1) are still comparable with average bulk values. This indicates the high potential of μPIM materials.