Effects of rolling temperature and subsequent annealing on mechanical properties of ultrafine-grained Cu-Zn-Si alloy

The effects of rolling temperature and subsequent annealing on mechanical properties of Cu-Zn-Si alloy were investigated by using X-ray diffraction, transmission electron microscope, electron back scattered diffraction and tensile tests. The Cu-Zn-Si alloy has been processed at cryogenic temperature (approximately 77 K) and room temperature up to different rolling strains. It has been identified that the cryorolled Cu-Zn-Si alloy samples show a higher strength compared with those room temperature rolled samples. The improved strength of cryorolled samples is resulted from grain size effect and higher densities of dislocations and deformation twins. And subsequent annealing, as a post-heat treatment, enhanced the ductility. An obvious increase in uniform elongation appears when the volume fraction of static recrystallization grains exceeds 25%. The strength-ductility combination of the annealed cryorolled samples is superior to that of annealed room temperature rolled samples, owing to the finer grains, high fractions of high angle grain boundaries and twins.