Microstructure and wear resistance of Fe-Al-Mn-Mo alloy after deep cryogenic treatment

The Fe-Al-Mn alloy is one of the alloy steels that is a candidate for cryogenic applications to replace the Fe-Cr-Ni alloy. The addition of Mo to the Fe-Cr-Ni alloy causes an increase in mechanical properties and corrosion resistance without changing the cryogenic properties. This research aims to investigate the effect of Deep Cryogenic Treatment (DCT) processing time on the microstructure, hardness, and wear of Fe-Al-Mn alloys with the addition of 0.5% Mo. The DCT process was carried out by soaking in liquid nitrogen at a temperature of -196°C for 1, 2, 3, 4, and 5 hours. Then it was returned to room temperature. The tests carried out were microstructure testing using an optical microscope, SEM, and EDS, hardness testing using the Vickers hardness method and wear testing using the Ogoshi method. The results of the microstructure test show that the Fe-Al-Mn-Mo alloy has a ferrite and austenite structure. The DCT process causes the ferrite structure to increase in size, while the austenite structure becomes smaller and more spread out between the ferrite grains. Hardness testing showed that the DCT process increased the hardness but not significantly. The wear test shows a decrease in the wear rate. Overall, the DCT process did not cause significant changes in microstructure and wear resistance.