Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 14: Topical session (Symposium MM): High entropy and compositionally complex alloys

MM 14.2: Vortrag

Dienstag, 2. April 2019, 10:45–11:00, H43

Quinary TWIP-TRIP high-entropy alloys: design, microstructure and mechanical properties — •Xiaoxiang Wu, Yuji Ikeda, Fritz Körmann, Dierk Raabe, and Zhiming Li — Max-Planck-Institut für Eisenforschung,Düsseldorf,Germany

Quinary FeMnNiCoCr HEAs have shown great potential in obtaining excellent combination of strength and ductility. By adjusting the atomic ratios of the five principal elements to reach appropriately low stacking fault energy (SFE), twinning-induced plasticity (TWIP) and/or transformation-induced plasticity (TRIP) effects can be introduced in the non-equiatomic quinary FeMnNiCoCr HEAs, leading to enhanced strength, ductility and working hardening capacity compared to the equiatomic HEA. In the present work, we combine ab initio calculation and experimental investigation to design various non-equiatomic quinary Fe60-x-yMnxNiyCo20Cr20 (at.%) HEAs. Three typical HEA compositions with comparably low SFE were chosen and alloys were then prepared and characterized. The results show that enhanced work hardening has been achieved by changing Ni concentration from 11 at.% to 6 at.% in the probed HEA system. In spite of the similar SFE level, the three HEAs under investigation demonstrate different primary deformation modes, changing from TRIP-dominant (with considerable TWIP), complete TWIP to TWIP-dominant (with negligible TRIP). The influences of SFE and the individual elements on the deformation modes are discussed to provide new insights into the further design of quinary TWIP-TRIP HEAs.