A strategy for enhancing the mechanical property of the precipitation-strengthened medium-entropy alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 819; p. 141390
• Main Authors: Yi, Hai-Long, Wei, Daixiu, Xie, Ren-Yi, Zhang, Yi-Fan, Kato, Hidemi
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05.07.2021; Elsevier BV
• Subjects: Alloys; Annealing; Chemical precipitation; Grain structure; Mechanical property; Medium entropy alloys; Medium-entropy alloy; Pre-straining; Precipitates; Precipitation; Ultimate tensile strength; Ultrafine structure; Annealing; Precipitation; Ultrafine structure; Pre-straining; Mechanical property; Medium-entropy alloy
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2021.141390

Medium-entropy alloys strengthened by the L12-type coherent precipitates were recently proposed, whereas the mechanical property still needs to be improved. Here, we demonstrated a strategy for notably improving the strength of the representative (CoCrNi)94Ti3Al3 alloy, in which the refinement of grain structures and the promotion of precipitation were concurrently achieved by pre-strain followed by aging. A refined grain structure containing incoherent σ-precipitates and a large number of coherent L12-precipitates was formed, which enhances the yield strength and ultimate tensile strength up to 1431 MPa and 1683 MPa respectively. Furthermore, decreasing pre-strain temperature or increasing strain further aids the enhancement. The present study opens an avenue for fabricating high-performance precipitation-strengthened alloys.