Investigation on microstructure and mechanical properties of 17-4PH stainless steels fabricated by materials extrusion additive manufacturing

Abstract

Materials extrusion additive manufacturing (MEAM) is currently attracting various industries as a modern manufacturing process that can produce complex parts with a lower cost than those of other additive manufacturing processes. In this study, the microstructure and mechanical properties of additively manufactured and wrought 17-4PH stainless steels as parts in original condition and in heat-treated under H900 condition were compared. The original specimen comprised martensite and δ-ferrite. After solution treatment, the δ-ferrite phase exhibited clear growth in martensite matrix. The precipitation strengthening due to aging treatment was evidenced by increases in tensile strength and hardness. Furthermore, strength coefficient (K) and strain hardening exponent (n) obtained from experiment were used as input data for simulation of tensile test. The simulation results for all specimens are in agreement with the experimental results. The findings from the simulation results are expected to be useful for prediction of mechanical behavior of complex parts fabricated by MEAM process.

Keywords

• additive manufacturing
• materials extrusion additive manufacturing
• 17-4ph stainless steel
• heat treatment
• precipitation strengthening
• finite element method