TY - JOUR
T1 - Portevin-Le Chatelier mechanism in face-centered-cubic metallic alloys from low to high entropy
AU - Tsai, Che Wei
AU - Lee, Chi
AU - Lin, Po Ting
AU - Xie, Xie
AU - Chen, Shuying
AU - Carroll, Robert
AU - Leblanc, Michael
AU - Brinkman, Braden A.W.
AU - Liaw, Peter K.
AU - Dahmen, Karin A.
AU - Yeh, Jien Wei
N1 - Funding Information:
The present work was supported by the Ministry of Science and Technology (Taiwan) grant numbers MOST 106-2218-E-007-019 . The support provided by the High-Entropy Materials Center from the Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education in Taiwan is greatly appreciated. We also thank John Weber, Greg Schwarz, and Abid Khan for helpful conversations. We gratefully acknowledge the support of the US National Science Foundation (NSF) through grants DMR 100520 , DMS 1069224 (KAD), DMR-1611180 and 1809640 (PKL), the Department of Energy (DOE) , NEUP 00119262 , DE-FE-0008855 (PKL) with Drs. Hess, Curry, Cooper, Farlkas, Shiflet, Cedro, Jensen, Tan, and Lesica as contract monitors. KAD and PKL thank DOE for the support through the project, DE-FE-0011194 , with the project manager, Dr. Mullen. PKL very much appreciates the support of the U.S. Army Research Office project ( W911NF-13-1-0438 ) with the program managers, Drs. Bakas, Mathaudhu, and Stepp.
Publisher Copyright:
© 2019 Elsevier Ltd. All rights reserved.
PY - 2019/11
Y1 - 2019/11
N2 - Serration phenomena during tensile testing on certain alloys with diffusing solute atoms (i.e., Portevin-Le Chatelier effect) have been observed for a long time, but detailed mechanisms are not fully clear yet. This study is intended to find the mechanism from different approaches verified by tensile testing on a series of single-phase face-centered-cubic (FCC) pure metal and alloys: Ni, CoNi, CoFeNi, CoCrFeNi, and CoCrFeMnNi, which range from low to high configurational entropy. The results of tensile tests, at strain rates from 1 × 10-5 to 1 × 10-2/s and temperature from room temperature to 700 °C, show that serrations occur on stress-strain curves of CoFeNi, CoCrFeNi, and CoCrFeMnNi alloys in their specific temperature and strain-rate regime. A mechanism for dislocation pinning is proposed and verified with theoretical calculation for the present substitutional alloys. The proposed mechanism involves the in-situ rearrangement of substitutional solute atoms by "local dislocation-core diffusion" and might also be applied to similar substitutional alloys.
AB - Serration phenomena during tensile testing on certain alloys with diffusing solute atoms (i.e., Portevin-Le Chatelier effect) have been observed for a long time, but detailed mechanisms are not fully clear yet. This study is intended to find the mechanism from different approaches verified by tensile testing on a series of single-phase face-centered-cubic (FCC) pure metal and alloys: Ni, CoNi, CoFeNi, CoCrFeNi, and CoCrFeMnNi, which range from low to high configurational entropy. The results of tensile tests, at strain rates from 1 × 10-5 to 1 × 10-2/s and temperature from room temperature to 700 °C, show that serrations occur on stress-strain curves of CoFeNi, CoCrFeNi, and CoCrFeMnNi alloys in their specific temperature and strain-rate regime. A mechanism for dislocation pinning is proposed and verified with theoretical calculation for the present substitutional alloys. The proposed mechanism involves the in-situ rearrangement of substitutional solute atoms by "local dislocation-core diffusion" and might also be applied to similar substitutional alloys.
KW - High-entropy alloy
KW - Medium-entropy alloy
KW - Portevin-Le Chatelier effect
KW - Serration mechanism
KW - Substitutional alloy
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U2 - 10.1016/j.ijplas.2019.07.003
DO - 10.1016/j.ijplas.2019.07.003
M3 - Article
AN - SCOPUS:85071414803
SN - 0749-6419
VL - 122
SP - 212
EP - 224
JO - International Journal of Plasticity
JF - International Journal of Plasticity
ER -