Study on the Forming and Mechanical Properties of 17-4PH Parts Fabricated by Metal Material Extrusion Additive Manufacturing Technique

Metal material extrusion (MME), using metal powder/polymer composite filament as raw material and undergoing the shaping-debinding-sintering (S-D-S) process to obtain pure metal products, is a low-cost metal additive manufacturing technique. However, the information related to the MME shaping process, conditions and product performance is rarely available. This study developed three types of self-made 17-4PH metal/polymer composite filament, and the ordinary material extrusion (ME) machine was used to build green parts to explore their formability. The feasibility of one-step thermal debinding/sintering was then studied using a muffle furnace. Subsequently, the sintered parts for static mechanical property test were formed with Ultrafuse 17-4PH composite filament through the S-D-S process, with their density, shrinkage and static mechanical properties studied. The results indicated that the one-step thermal debinding/sintering process was prone to defects such as oxidation and non-shrinkage. The maximum tensile strength and bending strength could reach 600 and 1200 MPa, respectively, and the hardness was about 230 HV.