The deformation mechanism and mechanical properties of pure copper and copper-zinc alloys with low stacking fault energy (SFE) were investigated primarily. In this paper, pure Cu and Cu-30%Zn samples were processed by surface mechanical attrition treatment (SMAT) at cryogenic temperature. The results show that Cu-30%Zn samples exhibit higher yield strength and better ductility by tensile tests at room temperature. With the same processing time of SMAT, the SMAT-ed Cu-30%Zn samples exhibit an optimized combination of strength and ductility compared with that of the SMAT-ed Cu samples. The in-situ electron backscatter diffraction (EBSD) tests show that there is a high density of geometrically necessary dislocations (GNDs) in SMAT-ed Cu-30%Zn samples with low SFE, thereby forming a strong hetero-deformation induced (HDI) stress strengthening and HDI hardening. Also, the twins promote the accumulation of geometrically necessary dislocations to enhance strength while maintaining good ductility in the Cu − 30%Zn samples.
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