TY - JOUR

T1 - Evidence of austenite memory in PH 15-5 and assessment of its formation mechanism

AU - Brandl, Dominik Christian

AU - Lukas, Marina

AU - Stockinger, Martin

AU - Ploberger, Sarah

AU - Ressel, Gerald

PY - 2019/8/15

Y1 - 2019/8/15

N2 - 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.

AB - 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.

KW - Austenite memory

KW - High temperature electron backscatter diffraction

KW - In-situ characterization

KW - Phase transformation

KW - Reversed austenite

KW - Supermartensitic stainless steel

KW - Supermartensitic stainless steelAustenite memoryReversed austenitePhase transformationIn-situ characterizationHigh temperature electron backscatter diffraction

UR - http://www.scopus.com/inward/record.url?scp=85065523057&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2019.107841

DO - 10.1016/j.matdes.2019.107841

M3 - Article

AN - SCOPUS:85065523057

VL - 176.2019

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

IS - August

M1 - 107841

ER -