• Influences of pass number and temperature on properties were much greater than the others. • Finite element modeling revealed non-uniform strain and flow patterns. • Porosity decreased after doing Exp-ECAP, bringing density closer to theoretical one. • XRD analyses verified increased dislocation densities after Exp-ECAP process. • Alloy reinforced with Al 2 O 3 , compared with SiO 2 , indicated higher strengths after processing. This research is concerned with the effects of expansion-equal channel angular pressing (Exp-ECAP) process parameters, as a bulk severe plastic deformation method, and the addition of Al 2 O 3 and SiO 2 nanoparticles on the mechanical behavior of AA6063-based nanocomposites. To carry out this study, a 2 (5-2) fractional factorial design was used, considering various process variables including temperature, ram velocity, pass number, nanoparticle type, and nanoparticle percentage. The yield stress and hardness of the deformed sample were also selected as the responses. The findings obtained from the design of experiment analysis showed that the process temperature, pass number, and nanoparticle type with respectively 59.6, 20.7, and 9.7 percent of contribution were the most effective parameters on the yield stress of the deformed part. These process variables also demonstrated the most significant impacts on the average hardness of the Exp-ECAP products. The highest amount of dislocation density was 28.8 × 10 14 m -2 and belonged to 3-passed sample reinforced with 2w% of Al 2 O 3 nanoparticles. Comparison of different findings indicated that this specimen experienced a higher enhancement in the strength due to its higher dislocation density and the morphology of the secondary phase, compared with the relevant sample reinforced with SiO 2 nanoparticles. Values of the yield and maximum strengths of this workpiece, subjected to 3 passes of Exp-ECAP, were respectively 217 MPa and 259 MPa, implying increases of 126% and 73% compared with the relevant undeformed reinforced component. The Al 2 O 3 -reinforced sample also possessed the highest hardness values before (≈58 HV) and after (≈89 HV) the Exp-ECAP process.
Tahmasbi et al. (Sun,) studied this question.