Effect of Cu3P addition on sintering behaviour of elemental powders in the composition of 465 stainless steel

The addition of Cu3P for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated were sintering temperature, sintering time and wt-% Cu3P. In vacuum sintering, effective sintering took place between 1300 and 1350 degrees C. The maximum sintered density of 7.44 g cm(-3) was achieved at 1350 degrees C for 60 min with 4-6 wt-% Cu3P. More than 6 wt-% Cu3P content and temperature > 1350 degrees C caused slumping of the specimens. The sintered specimens were heat treated and a maximum ultimate tensile strength (UTS) of 767 MPa was achieved with 4 wt-% Cu3P content. The maximum hardness of 45.5 HRC was achieved in heat treated condition with 4 wt-% Cu3P content. Above 4 wt-% Cu3P content increase in density was observed whereas the response to heat treatment decreased. Fracture morphologies of the sintered specimens were also reported. A comparison of sintering behaviour and mechanical properties of elemental powders with prealloyed powders was also given in the present study.