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Two different alloys were developed from the mixtures of pre-alloyed powders consisting of ferroalloys to get the required composition of austenitic stainless steel via the powder metallurgy techni...

In the current study, mechanical properties of hot pressed, solution treated and aged austenitic stainless steels (21-4N) for were evaluated by varying the percentage of yttria addition. The milled powders were vacuum hot pressed at 1,200°C with a pressure level of 56 MPa with a holding period of 2 hrs under the vacuum level of 10-2 torr. Hot pressed samples were solution treated at 1,200°C for a period of 2 hrs and immediately subjected to water quenching to dissolve more grain boundary carbides. Further, to achieve the desired hardness samples were aged at 750°C held for 4 hrs followed by air cooling. Optical micrographs and SEM-EDS studies reveal austenitic grain with grain boundary carbides in the hot pressed condition. After solution treatment these precipitates disappears which was confirmed through SEM-EDS. Austenitic stainless steel containing 0.3 wt% yttria has attained higher tensile strength of 598 MPa in the age hardened condition.