Evidence of austenite memory in PH 15-5 and assessment of its formation mechanism

Dominik Christian Brandl, Marina Lukas, Martin Stockinger, Sarah Ploberger, Gerald Ressel

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7 Citations (Scopus)

Abstract

Austenite memory and subsequent spontaneous recrystallization during austenitization is stated for some types of soft martensitic stainless steels such as X4CrNiMo16-5-1 or 13Crsingle bond5Ni but have not been proposed for the commercial alloy PH15-5 until now. However, the understanding of the austenitization behavior is defined to be crucial as it influences grain size, dislocation density of austenite and thus the final mechanical properties of the material.

Therefore, this study investigates the austenitization behavior of PH15-5 by means of in-situ high temperature electron back scatter diffraction of continuous austenitization and directly evidences austenite memory also in this alloy. In order to characterize the austenite formation mechanism in detail, dilatometer, in-situ X-ray diffraction and confocal laser scanning microscope experiments have been carried out. Corroborated with thermokinetic DICTRA simulations, a diffusion controlled transformation exhibiting austenite memory is evidenced. The in-situ high temperature electron backscatter diffraction data in comparison with recent literature indicates the inheritance of geometrically necessary dislocations from martensite to austenite. Therefore, a basic model is postulated in order to describe the inheritance of geometrically necessary dislocations due to a diffusion controlled transformation process.
Original languageEnglish
Article number107841
Number of pages9
JournalMaterials and Design
Volume176.2019
Issue numberAugust
Early online date9 May 2019
DOIs
Publication statusPublished - 15 Aug 2019
Externally publishedYes

Keywords

  • Austenite memory
  • High temperature electron backscatter diffraction
  • In-situ characterization
  • Phase transformation
  • Reversed austenite
  • Supermartensitic stainless steel

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