The origin of negative stacking fault energies and nano-twin formation in face-centered cubic high entropy alloys

2017 ◽  
Vol 130 ◽  
pp. 96-99 ◽  
Author(s):  
Y.H. Zhang ◽  
Y. Zhuang ◽  
A. Hu ◽  
J.J. Kai ◽  
C.T. Liu
2018 ◽  
Vol 93 ◽  
pp. 269-273 ◽  
Author(s):  
S.F. Liu ◽  
Y. Wu ◽  
H.T. Wang ◽  
J.Y. He ◽  
J.B. Liu ◽  
...  

Author(s):  
T Tsuru ◽  
Ivan Lobzenko ◽  
Daixiu Wei

Abstract High-entropy alloys (HEA) have been receiving increased attention for their excellent mechanical properties. Our recent study revealed that Si-doped face-centered cubic (FCC) HEAs have great potential to improve both strength and ductility. Here, we carried out first-principles calculations in cooperation with Monte Carlo simulation and structural factor analysis to explore the effect of Si addition on the macroscopic mechanical properties. As a result, Si addition increased the local lattice distortion and the stacking fault energy. Furthermore, the short-range order formation in Si-doped alloy caused highly fluctuated stacking fault energy. Thus, the heterogeneous solid solution states in which low and high stacking fault regions are distributed into the matrix were nucleated. This unique feature in Si-doped FCC-HEA induces ultrafine twin formation in Si-doped alloys, which can be a dominant factor in improving both strength and ductility.


2021 ◽  
Vol 11 (6) ◽  
pp. 2832
Author(s):  
Haibo Liu ◽  
Cunlin Xin ◽  
Lei Liu ◽  
Chunqiang Zhuang

The structural stability of high-entropy alloys (HEAs) is closely related to their mechanical properties. The precise control of the component content is a key step toward understanding their structural stability and further determining their mechanical properties. In this study, first-principle calculations were performed to investigate the effects of different contents of each component on the structural stability and mechanical properties of Co-Cr-Fe-Ni HEAs based on the supercell model. Co-Cr-Fe-Ni HEAs were constructed based on a single face-centered cubic (FCC) solid solution. Elemental components have a clear effect on their structure and performance; the Cr and Fe elements have an obvious effect on the structural stability and equilibrium lattice constant, respectively. The Ni elements have an obvious effect on stiffness. The Pugh ratios indicate that Cr and Ni addition may increase ductility, whereas Co and Fe addition may decrease it. With increasing Co and Fe contents or decreasing Cr and Ni contents, the structural stability and stiffness of Co-Cr-Fe-Ni HEAs are improved. The structural stability and mechanical properties may be related to the strength of the metallic bonding and covalent bonding inside Co-Cr-Fe-Ni HEAs, which, in turn, is determined by the change in element content. Our results provide the underlying insights needed to guide the optimization of Co-Cr-Fe-Ni HEAs with excellent mechanical properties.


JOM ◽  
2021 ◽  
Author(s):  
Abhishek Sharma ◽  
Bharat Gwalani ◽  
Sriswaroop Dasari ◽  
Deep Choudhuri ◽  
Yao-Jen Chang ◽  
...  

2021 ◽  
Vol 202 ◽  
pp. 124-134
Author(s):  
Yakai Zhao ◽  
Jeong-Min Park ◽  
Jae-il Jang ◽  
Upadrasta Ramamurty

2020 ◽  
Vol 51 (11) ◽  
pp. 5612-5616
Author(s):  
Motomichi Koyama ◽  
Haoyu Wang ◽  
Virendra Kumar Verma ◽  
Kaneaki Tsuzaki ◽  
Eiji Akiyama

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