The effect of sintering temperature on the structure and mechanical properties of medical-grade powder metallurgy stainless steels

Nanostructured medical-grade stainless steel powders with the chemical composition of ASTM F2581 were liquid-phase sintered with 6 wt.% Mn-Si additive at different temperatures ranging from 1000 °C to 1300 °C. The effect of sintering temperature on the structure and mechanical properties of the samples was investigated. Structural characteristics like porosity, austenite crystallite/grain size, and retained ferrite were analyzed by optical microscopy, Archimedes densitometry, X-ray diffraction, transmission electron microscopy, and ferritometry. The corresponding results showed that residual porosity in the sintered specimens was reduced by increasing the sintering temperature; in contrast, the crystallite/grain sizes were enhanced. The study of the mechanical properties, including hardness, compressive, and abrasive wear behaviors, of the samples indicated that the optimum mechanical properties were obtained for the sintering temperature of 1150 °C, which were superior to those of AISI 316L stainless steel used as a conventional biomaterial.