Back to Search Start Over

Temperature-dependent hardening contributions in CrFeCoNi high-entropy alloy.

Authors :
Naeem, Muhammad
He, Haiyan
Harjo, Stefanus
Kawasaki, Takuro
Lin, Weitong
Kai, Ji-Jung
Wu, Zhenduo
Lan, Si
Wang, Xun-Li
Source :
Acta Materialia. Dec2021, Vol. 221, pN.PAG-N.PAG. 1p.
Publication Year :
2021

Abstract

We studied the deformation behavior of CrFeCoNi high-entropy alloy by in situ neutron diffraction at room temperature, intermediate low temperature of 140 K, low temperatures of 40 K (no serrated deformation) and 25 K (with massive serrations). The evolution of lattice strain and texture along different grain orientations provided distinct insights into deformation behavior at low temperatures. The in situ data showed an early activation of stacking faults and a higher stacking fault probability with decreasing test temperature. The stacking fault probability reached ∼4.7% at low temperatures. The dislocation density at 40 and 25 K evolved similarly and had a very high value of ∼9.2 × 1015 m−2. However, twin fault probability at 25 K (∼6%) was higher than that at 40 K (∼5%). The samples at 40 and 25 K deformed uniformly and lacked any necking region, thus imparting an excellent ductility of ∼58%. The contributions from different deformation mechanisms to the yield strength and strain hardening have been estimated. The athermal contributions to the yield strength were ∼183 MPa at all temperatures, while the Peierls stress increased significantly at low temperatures (from 148 MPa at room temperature to 493 MPa at 25 K). Dislocations contributed to ∼94% strain hardening at room temperature. Although the dislocation strengthening remained the major hardening mechanism at very low temperatures, the planar faults contribution increased steadily from 6% at room temperature to 28% at 25 K. [Display omitted] [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
13596454
Volume :
221
Database :
Academic Search Index
Journal :
Acta Materialia
Publication Type :
Academic Journal
Accession number :
153960522
Full Text :
https://doi.org/10.1016/j.actamat.2021.117371