|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Advances in Multi-Principal Elements Alloys X
||Heterogeneous ultrafine grain formation by severe plastic deformation in CrMnFeCoNi HEAs
||Koichi Tsuchiya, Jangho Yi, Sangmin Lee, Je In Lee
|On-Site Speaker (Planned)
Process of grain refinement by severe plastic deformation by high-pressure torsion (HPT) was investigated for Cr20Mn20Fe20Co40-xNix (x=0~40). Samples with 0~5atl%Ni are composed of HCP and FCC phases after the heat treatment, while others are in the FCC single phase state. For the 15~20Ni alloys, HPT led to a drastic increase in micro-Vickers Hardness (Hv). This can be attributed to rapid progress of grain refinement. BSD-SEM observations revealed that initial formation of lamellar structures of about 100 nm width separated by nanotwins. This accelerates an increase in dislocation density and led to formation of equiaxed nanograins (~50 nm) by continuous dynamic recrystallization. Tensile properties of HPT deformed samples were studied. Large tensile elongation, typical of FCC HEAs, was much reduced by nanograin formation. But Ni10 and Ni 15 after HPT of 1/2 rotation still exhibited about 10% total elongation with high the tensile strength up to 1.5 GPa.
||High-Entropy Alloys, Mechanical Properties, Phase Transformations