Microstructure evolution and twinning-induced plasticity (TWIP) in hcp rare-earth high-and medium-entropy alloys (HEAs and MEAs) due to tensile deformation

Title data

Rosenkranz, Laura ; Lan, Qianqian ; Heczko, Milan ; Egan, Ashton J. ; Mills, Michael J. ; Feuerbacher, Michael ; Glatzel, Uwe:
Microstructure evolution and twinning-induced plasticity (TWIP) in hcp rare-earth high-and medium-entropy alloys (HEAs and MEAs) due to tensile deformation.
In: Journal of Applied Physics. Vol. 136 (2024) Issue 2 . - 025101.
ISSN 1089-7550
DOI: https://doi.org/10.1063/5.0207181

Official URL:

Abstract in another language

The microstructure evolution due to the tensile deformation of the equiatomic quinary high-entropy alloy Ho-Dy-Y-Gd-Tb (HEA-Fb) is assessed. HEA-Fb has extraordinarily similar alloying elements. It is one of the few hexagonal-close-packed single-phase representatives of HEA. HEA-Fb is compared to the equiatomic quaternary medium-entropy alloy (MEA) Ho-Dy-Gd-Tb with no Y (4-Y). For a hexagonal HEA, in contrast to the cubic HEA, little information on plastic deformation and underlying mechanisms is available. A detailed study using electron microscopy-based multi-scale characterization (SEM, S/TEM, and STEM-EDS) explains significant differences between the ductile behavior of the quaternary MEA 4-Y and the brittle behavior of the quinary HEA-Fb at room temperature. Twinning during plastic deformation is decisive for ductility, which challenges the widely discussed high-entropy effect on the mechanical behavior of the HEA. For the quaternary MEA 4-Y, a twinning-induced plasticity effect is found. In the latter, oxidized twins are present in the undeformed state. In both alloys, the twin orientations are indexed as [-2201], while the matrices have the perpendicular [11-20] orientation. Additionally, the analysis of twin structures confirms the importance of twin boundaries as obstacles for dislocations and stacking fault mobilities. The results are discussed in the context of the existing knowledge gaps in the field of hexagonal MEAs and HEAs.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Keywords:	Entropy; Crystallographic defects; Mechanical properties; Microstructural properties; Stress strain relations; Crystal twinnings; Transmission electron microscopy; Tensile properties
Institutions of the University:	Faculties Faculties > Faculty of Engineering Science > Chair Metals and Alloys > Chair Metals and Alloys - Univ.-Prof. Dr.-Ing. Uwe Glatzel
Result of work at the UBT:	Yes
DDC Subjects:	600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited:	16 Aug 2024 05:14
Last Modified:	16 Aug 2024 05:14
URI:	https://eref.uni-bayreuth.de/id/eprint/90210