Enhancing mechanical properties and microstructure evolution of hybrid AZ61-5SiC-0.5CNTs composite during equal channel angular pressing

Equal channel angular pressing (ECAP) is one of widely used severe plastic deformation methods for improving performance of metallic materials. In this work, the effects of the ECAP on the microstructural evolution and mechanical properties of the AZ61-5SiC-0.5CNTs composite were studied systematically. The results revealed that ECAP can effectively reduce the porosity of the AZ61-5SiC-0.5CNTs composite, refine grains, weaken basal texture, and promote the further dispersion of CNTs, which can optimize the microstructure of the composite. However, the large shear effect of ECAP also leads to the destruction of the structural integrity of the CNTs and thus reduces the strengthening effect. Due to the combined effects of grain refinement, porosity changes, texture evolution, and structural damage of CNTs, the composites reached the highest strength after 2 ECAP passes at 250 degree celsius. The yield and tensile strengths were increased to 383 MPa (+11.0 %) and 445 MPa (+8.0 %), respectively, while the elongation was marginally reduced, but remained around 6 %.