Effects of cold-rolling and subsequent annealing on the nano-mechanical and creep behaviors of CrCoNi medium-entropy alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 839; p. 142802
• Main Authors: Sun, Shuo, Zai, Wei, Chen, Yan, Zhao, Liang, Sun, Guixun, Hu, Jiangjiang, Han, Shuang, Lian, Jianshe
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 06.04.2022; Elsevier BV
• Subjects: Alloys; Annealing; Cold; Cold rolling; Creep; Creep strength; Dislocation density; Entropy; Grain refinement; Grain size; Medium entropy alloys; Medium-entropy alloy; Microstructure; Nanoindentation; Recrystallization; Short range order; Strengthening mechanisms; Temperature dependence; Thermomechanical treatment; Annealing; Cold-rolling; Creep; Strengthening mechanisms; Medium-entropy alloy; Nanoindentation
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2022.142802

The influences of thermomechanical treatment on the microstructural evolution and nano-mechanical behaviors of CrCoNi medium-entropy alloy (MEA) were systematically studied through a series of nanoindentation experiments. Cold-rolling induced substantial grain refinement and during subsequent annealing, the CrCoNi MEA exhibited a highly temperature-dependent recrystallized microstructure characterized by significant variations in grain size, dislocation density, and twin fraction with increasing annealing temperature. The hardness of the cold-rolled sample increased with annealing temperature, reaching its highest value at 600 °C and then decreasing gradually. Annealing was also found to influence the creep behaviors of the CrCoNi MEAs. A cold-rolled sample annealed at 700 °C exhibited the highest resistance to creep. The results of a detailed microstructure examination, calculations, and theoretical analysis revealed that annealing twins play a key role in increasing both the strength and the creep resistance of the CrCoNi MEAs. Short-range order clusters also contributed to the strength and creep resistance. [Display omitted] •The microstructural evolution induced by cold-rolling and subsequent annealing in CrCoNi medium-entropy alloy was explored.•Nano-mechanical and creep behaviors of the CrCoNi alloys experienced thermomechanical treatment were systematically investigated.•Annealing twins play a key role not only in elevating the strength but also in enhancing the creep resistance of the CrCoNi alloys.