Effect of Sinter Hardening on Microstructure and Mechanical Properties of Astaloy 85Mo

Effect of sinter hardening on the microstructure, density, hardness and tensile properties of Astaloy 85Mo+ 0.7% graphite was investigated. For this purpose, Astaloy 85Mo, a pre-alloyed powder, was mixed with 0.7% UF4 graphite and then pressed in single action die and sintered at 1120 °C for 30 min in N2-10%H2 atmosphere. Then samples were cooled from 0.5 to 3 °C/s sintering temperature in accordance with different cooling rates. The difference in microstructure, hardness, density and tensile properties of the samples associated with different cooling rates from sintering temperature has been investigated. The results show that the microstructure remains bainitic by changing cooling rate, but it becomes finer and then the hardness and tensile strength of the samples will increase by increasing the cooling rate from sintering temperature.