Abstract This study mainly investigates the influence of artificial aging at 480 °C, 520 °C and 620 °C on the microstructure and mechanical properties of metal injection molding (MIM) 17-4PH. The results show… Click to show full abstract
Abstract This study mainly investigates the influence of artificial aging at 480 °C, 520 °C and 620 °C on the microstructure and mechanical properties of metal injection molding (MIM) 17-4PH. The results show the microstructure of the as-sintered MIM 17-4PH to be mainly composed of lath martensite, δ-ferrite, and nodular SiO2 inclusions. The effect of precipitation hardening is to strengthen the MIM 17-4PH by the precipitation of a large number of fine spherical e-Cu phases on the lath martensite matrix, which effectively block the movement of dislocations. The highest hardness is obtained by artificial aging at 480 °C for 4 h. As the aging temperature increases, the e-Cu phase grows coarser, which results in over aging of the MIM 17-4PH and decreases the hardness.
               
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