금속분말 사출성형법으로 제조된 스테인리스 316L 강의 소결조건에 따른 기계적 성질
= Effects of Sintering Conditions on the Mechanical Properties of Metal Injection Molded 316L Stainless Steel
In this work, tensile and fatigue properties of the metal injection molded 316L stainless steel were studied with the variation of sintering conditions. It was found that increasing sintering temperature and time resulted in a decrease in the porosity along with an increase in the grain size. With decreasing porosity, tensile strength and elongation increased, while yield strength maintained constant, which was attributed to the balanced effects of decrease of porosity and grain coarsening. Tensile strength and elongation were found to be largely dependent on the porosity rather than on the grain size since the fracture occurred mainly by microvoid growth and coalescence. A quantitative analysis on yield strength was made by considering the classical Hall-Petch equation and mechanistic models for yield strength of porous materials. The fatigue crack growth resistance at low ΔK level was not largely decreased when the porosity was increased up to 8%, but was significantly decreased when the porosity was increased to 17%. It was discussed in relation to the intrinsic nature of pore morphology and the extrinsic nature of crack closure.
KISS
