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Two nearly degenerate positive-parity bands with the πg9/22⊗νg9/2−1 configuration and three nearly degenerate negative-parity bands with the πg9/2(p3/2,f5/2)⊗νg9/2−1 configuration have been identified in $^{81}$Kr. They are interpreted as chiral doublet bands and pseudospin-chiral triplet bands, which is supported by the constrained covariant density functional theory and the multiparticle plus rotor model calculations. The present work reports two new chiral configurations πg9/22⊗νg9/2−1 and πg9/2(p3/2,f5/2)⊗νg9/2−1, and the first example of pseudospin-chiral triplet bands involving the π(p3/2,f5/2) pseudospin doublet.

Effect of coherent L1 2 nanoprecipitates on the tensile behavior of a novel-designed Al 0.2 CrFeCoNi 2 Cu 0.2 high-entropy alloy is investigated in this study. Different heat treatments after cold rolling were used to achieve the alloys with two different microstructures. One is composed of a fcc matrix and coherent L1 2 (Ni,Cu) 3 Al nanoprecipitates after annealing at 700 ° C for 20 h; the other owns a fcc single-phase structure after annealing at 800 °C for 1 h as reference. Furthermore, the two alloys have nearly identical average grain sizes (~4.5 µm), and thus the exclusive effect of L1 2 nanoprecipitates could be identified by directly comparing their tensile behaviors. It is shown that the presence of L1 2 nanoprecipitates results in increases of 259 MPa and 316 MPa in the yield strength and ultimate tensile strength, respectively, accompanied by the maintenance of a high elongation (30.4%). This excellent strengthening effect is explained by the interaction between dislocations and L1 2 nanoprecipitates during the tensile straining process. Dislocation shearing of the L1 2 nanoprecipitates, which is evidently observed and also verified by the yield strength increment calculation, leads to predominant planar dislocation glide and the formation of crystallographically aligned slip bands as the main deformation mechanism, eventually resulting in a considerable work-hardening capacity enhancement with almost none harm to the elongation.

Vinogradov et al. [1] reported that the stacking fault energy (SFE) of Cu– x Ge alloys with germanium concentration varying from 0, 0.1, 5.7 to 9.0 at% alters from 78, 54, 15 to 8 mJ/m 2 , respectively. In the present study, the Cu– x Ge alloys were prepared by forging at the liquid nitrogen temperature and their mechanical properties were systematically investigated. Results indicated that the microhardness, strength and uniform elongation of Cu– x Ge alloys were simultaneously improved by lowering the SFE. X-ray diffraction measurements revealed that a reduction in SFE leads both to a decrease in grain size and an increase in dislocation density, twin density and microstrain for the cryogenic forged samples and these contribute to the improvements in the mechanical properties. This work demonstrates that high strength and excellent ductility can be simultaneously achieved by lowering SFE of the metals.