Fabrication of 17-4PH stainless steel by metal material extrusion: Effects of process parameters and heat treatment on physical properties

• The −45°/45° raster angle results in the dispersion of pores and enhanced interlayer bonding, which in turn creates a structure that is stress-dispersion-friendly. • Sintering at 1380 °C has been found to maximise densification and to substantially improve the mechanical properties of 17-4PH stainless steel specimens through active atomic diffusion. • The heat treatment of optimally fabricated parts has been observed to induce grain refinement and element-rich regions, which in turn leads to a simultaneous enhancement in strength and ductility. Metal material extrusion (MEX) has emerged as a promising technology for producing metal parts, offering advantages in cost-effectiveness and production efficiency. However, its adoption in high-performance applications is limited by insufficient understanding of process-property relationships. To address this gap and advance metal MEX technology, this study methodically analyzed the effects of various process variables. The raster angle setting of −45°/45° resulted in a structure with more dispersed pore formation and enhanced interlayer bonding, leading to higher tensile strength and elongation compared to those obtained at 0°/90°. When exploring sintering temperature effects at the optimal raster angle (−45°/45°), results revealed improved specimen densification at high temperatures, leading to enhanced microstructure and mechanical properties. Heat treatment on specimens fabricated under optimal conditions (raster angle: −45°/45°; sintering temperature: 1380 °C) further enhanced mechanical properties due to various microstructural changes, including grain refinement and formation of element-rich regions, acting in combination. Through step-by-step control of process variables, this research presents a method for tailoring the physical properties of 17-4PH stainless steel to suit different application fields. These findings expand the potential of metal MEX applications in industries requiring high-performance components and advance metal additive manufacturing technology by demonstrating precise property control.