Effect of Y2O3 addition and cooling rate on mechanical properties of Fe-24Cr-20Ni-2Mn steels by powder metallurgy route

The effect of yttria (Y2O3) addition (0 Wt. %, 0.5 Wt. % and 1 Wt. %) on micro-structural changes and mechanical properties of Fe-24Cr-20Ni-2Mn steels were investigated by powder metallurgy (P/M) route. The consolidation process was conducted with different cooling rates (5 °C/min, 8 °C/min and 10 °C/min) to understand the precipitate formation. The powders were cold compacted at 650 MPa pressure and then sintered at 1200 °C for 1 hour under vacuum atmosphere. The structural changes of sintered pellets were examined by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties such as hardness (HV), tensile strength (MPa) and elongation (%) were measured at 28 °C and 300 °C. The addition of Y2O3 has a momentous effect on the mechanical properties of Fe-24Cr-20Ni-2Mn steels. The degree of precipitation varies with rate of cooling used during the sintering process.