摘要

A coarse-grained Cu-36Zn-2Pb alloy with an initial grain size of 54 mu m was processed by high-pressure torsion (HPT) at room temperature under an applied pressure of 6.0 GPa through 1-10 turns, and the evolution of microstructure and microhardness was investigated. Analysis by X-ray diffraction (XRD) showed that in HPT processing the beta'-phase transforms to an alpha-phase and a {111} texture is formed. Microscopic examination showed that dislocations were first formed at equivalent strains of not more than 25 and when the equivalent strain increased to 40 there was evidence for twins and secondary twinning. Fine grains were formed with an increase in equivalent strain to 100 and with further straining these refined grains acted as precursors for additional grain refinement. The refined equiaxed grain size was 250 nm after HPT through an equivalent strain of 100 and the results show the microhardness reached a saturation value of 220 Hv.