High pressure torsion processing of maraging steel 250: Microstructure and mechanical behaviour evolution

Kevin Jacob, Deepesh Yadav, Saurabh Dixit, Anton Hohenwarter, Balila Nagamani Jaya

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2 Citations (Scopus)


Maraging steels are precipitation strengthened martensitic steels with an unusual combination of strength and ductility. High Pressure Torsion (HPT) has been used in this study to produce maraging steel 250 grade (AMS 6512) with finer laths and higher dislocation density, both of which act as nucleation sites for precipitation, and reverted austenite formation. This study focusses on the effect of such a processing on the evolution of the microstructure, including kinetics of precipitation, recrystallisation and austenite reversion as well as the stability of the precipitates thus formed. It was found that the aging kinetics accelerated substantially in the HPT processed samples, by achieving peak aging conditions at considerably shorter temperature/time durations and also a peak hardness higher than the as-received sample by 41%. Detailed microstructural characterisation revealed a change in the precipitate morphology from spherical to plate like form in the overaged conditions. The impact of this on mechanical response of these steels was quantified using tensile tests. A 70% increase in ultimate tensile strength was achieved in HPT processed samples after peak aging. Changes in strength and ductility were correlated to the changes in the microstructure and their impending contributions to different strengthening mechanisms at play to enable better design of maraging steels.
Original languageEnglish
Article number140665
Number of pages13
JournalMaterials Science and Engineering A
Issue number20 January
Early online date14 Dec 2020
Publication statusPublished - 20 Jan 2021

Bibliographical note

Publisher Copyright: © 2020 Elsevier B.V.


  • High pressure torsion
  • Maraging steels
  • Mechanical behaviour
  • Precipitation kinetics

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