Powder injection molding of a 17-4 PH stainless steel and the effect of sintering temperature on its microstructure and mechanical properties

The 17-4 PH stainless steel powders with average diameter of 10 mum were injection-molded into plate-type tensile specimens. Sintering of the compacts was carried out at the various temperatures ranging from 900 to 1350 degreesC after solution extraction and thermal decomposition. Sintering behavior of the powder injection-molded specimens and room temperature tensile properties of sintered specimens were investigated. With increase in the sintering temperature, relative density of the specimens increased from 61% at 900 degreesC to 99% at 1350 degreesC. The pores of sintered specimens appeared to become more rounded in shape and isolated in distribution as the sintering temperature was increased. The tensile strength of sintered specimens was found to increase almost linearly with the sintering temperature, which could not be explained with any model reported so far. The elongation was enhanced with the closure of pores with proceeding of sintering into the intermediate and the final stages. (C) 2002 Elsevier Science B.V. All rights reserved.