Examining the effect of multi-pass FSP on microstructure, texture, and mechanical properties of hybrid reinforced AA2024-T351 surface composites
Md Saquib Bin Reyaz, Joginder Singh, Shallender Singh Bhati, Husain Mehdi, Subhash Mishra
Abstract
This study examines the effects of multi-pass friction stir processing (MPFSP) on the microstructure, texture, and mechanical performance of hybrid aluminum matrix composites (HAMCs). One, two, four, and six FSP passes with an equal volume fraction of 50% B₄C and 50% Al₂O₃ were utilized to fabricate the surface composites. Results show significant grain refinement, with mean grain size decreasing from 7.32 μm to 2.31 μm and an increase in high-angle grain boundaries from 74.13% to 94.61%. The inverse pole figure (IPF) texture analysis reveals a notable increase in texture intensity from 2.34 to 7.01. Mechanical properties of the HAMCs improve substantially, with ultimate flexural strength increasing by 20.42% (498 MPa to 602 MPa) and hardness by 9.59% (146 hV to 160 hV). Wear resistance is also enhanced, with a decrease in the coefficient of friction (0.39 to 0.24) and wear rate (0.00396 mm3/m to 0.00337 mm3/m). These improvements are attributed to uniform reinforcement dispersion, grain refinement, increased high-angle grain boundaries, and texture strengthening due to intense plastic deformation and dynamic recrystallization. The findings demonstrate the effectiveness of MPFSP in enhancing the microstructure and mechanical properties of surface composites. The process induces significant grain refinement and texture strengthening, leading to improved mechanical performance.