Excellent strength-ductility combination of Cr_(26)Mn_(20)Fe_(20)Co20Ni_(14) high-entropy alloy at cryogenic temperatures

In the present study,a face-centered cubic non-equiatomic Cr_(26)Mn_(20)Fe_(20)Co20Ni_(14) high-entropy alloy(HEA)with a low stacking fault energy of 17.6 mJ m^(−2) was prepared by vacuum induction melting,forging and annealing processes.The recrystallized sample is revealed to exhibit an excellent combination of strength and ductility over a wide temperature range of 4.2–293 K.With decreasing temperature from 293 to 77 K,the ductility and ultimate tensile strength(UTS)gradually increase by 30% to 95% and 137% to 1020 MPa,respectively.At the lowest temperature of 4.2 K,the ductility keeps 65% and the UTS increases by 200% to 1300 MPa,which exceed those published in the literature,including conventional 300 series stainless steels.Detailed microstructural analyses of this alloy reveal a change of deformation mechanisms from dislocation slip and nano-twinning at 293 K to nano-phase transformation at 4.2 K.The cooperation and competition of multiple nano-twinning and nano-phase transformation are responsible for the superior tensile properties at cryogenic temperatures.Our study provides experimental evidence for potential cryogenic applications of HEAs.

Morphological and physiological analysis of narrow and striped leaf 1(nsl1) mutant of rice(Oryza sativa L.) and the gene mapping

The shape and color of rice leaves are important agronomic traits that directly influence the proportion of sunlight energy utilization and ultimately affect the yield and quality.A new mutant exhibiting stable inheritance was identified as derived from ethyl methane sulfonate(EMS)-treated restorer Jinhui 10,tentatively named as narrow and striped leaf 1(nsl1).The nsl1 displayed pale white leaves at the seeding stage and then white striped leaves in parallel to the main vein at the jointing stage.Meanwhile,its leaf blades are significantly narrower than the control group of Jinhui 10.The chloroplast structures of cells in the white striped area of the nsl1 mutant break down,and the photosynthetic pigments are significantly lower than that of the wild type.Moreover,fluorescence parameters,such as F0,F v/F m,U psII,qp,and ETR,in the nsl1 mutant are significantly lower than those of the wild type,and the photosynthetic efficiency is also significantly decreased.These changes in leaf color and shape,together with physiological changes in the nsl1,result in smaller plant height and a decrease in the most important agronomic traits,such as the number of grains per panicle,grain weight,etc.Genetic analysis shows that the narrow and striped traits of the nsl1 mutant are controlled by a single recessive nuclear gene,which is located between InDel 16and InDel 12 in chromosome 3.The physical distance is204 kb.So far,no similar genes of such leaf color and shape in this area have been reported.This study has laid a solid foundation for the gene cloning and function analysis of NSL1.