Abstract: The process of equal channel angular pressing(ECAP)of 7075 aluminium alloy is numerically simulated using a finite element software to predict the microstructure grain size. The method of the combining application of finite element simulation and experimental analysis is explored to investigate the variation of microstructure grain size and then tensile mechanics performance test at room temperature is done between ECAP sample and initial sample, which fracture surface is watched by scanning electron microscope(SEM). The simulated results show that the grain size of sample decreases remarkably after ECAP, which reduces from 40 μm to 24.6 μm. After the experiment of ECAP the grain sizes of the sample P1, P2 and P3 are 23.8 μm, 23.7 μm, 23.9 μm and they are very similar. The result comparing simulative prediction with the experimental analysis demonstrates that there is a good fit in grain refinement between the two and the tensile breaking strength increases from 547 MPa to 619 MPa as well as the reduction of area increasing from 7.1% to 10.6% after ECAP. The fracture dimple is deep and great and so the strength and plasticity are improved obviously.

Key words: microstructure grain size prediction;equal channel angular pressing(ECAP);continuous dynamic recrystallization;7075 aluminum alloy