Achieving room temperature superplasticity in the Zn-0.5Cu alloy processed via equal channel angular pressing

The Zn-0.5Cu alloy was investigated in as-cast, homogenized state and after carrying out equal channel angular pressing four times at room temperature via route B-c. Microstructure analysis using light microscopy and SEM/EBSD was performed, as well as tensile tests, misorientation angle distribution and texture analysis. The initial microstructure with the average grain size of 560 pm was refined to a grain size of approx. 1 mu m. The obtained microstructure consists of uniaxial grains separated mostly by high angle grain boundaries. Mechanical characterization was performed at strain rates from 2 x 10(-6) s(-1) to 1 s(-1) at room temperature. Ultrafine-grained zinc-copper alloy exhibited 510% elongation with the strain rate sensitivity equal 0.31, which was the first observation of room temperature superplasticity in Zn-Cu alloys. Based on the microstructure, misorientation angle and texture analysis, the main operating deformation mechanisms were distinguished for samples deformed at strain rates from 2 x 10(-5) s(-1) to 10(-1) s(-1).