Title: Influence on mechanical properties of hot pressed, solution treated and age hardened 21-4N ODS alloy developed through pre-alloyed powders

Authors: R. Mariappan; Arun Prasad Murali; G. Dharmalingam; D. Siva Prakasham

Addresses: Department of Mechanical Engineering, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Avadi, Chennai-600062, Tamil Nadu, India ' Department of Mechanical Engineering, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Avadi, Chennai-600062, Tamil Nadu, India ' Department of Mechanical Engineering, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Avadi, Chennai-600062, Tamil Nadu, India ' Centre for Automotive Energy Materials, ARCI, IITM Research Park, Chennai – 600113, Tamil Nadu, India

Abstract: 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.

Keywords: 21-4N austenitic stainless steel; oxide dispersion strengthening; mechanical alloying; vacuum hot pressing; solution treatment; aging treatment.

DOI: 10.1504/IJMATEI.2020.106661

International Journal of Materials Engineering Innovation, 2020 Vol.11 No.2, pp.127 - 144

Received: 03 Apr 2019
Accepted: 16 Jul 2019
Published online: 16 Apr 2020 *

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