Microstructure investigation, mechanical properties and wear behavior of Al 1050/SiC composites fabricated by friction stir processing (FSP)

Abstract

Friction stir processing (FSP) is used to produce Al/SiC composites on the surface of Al 1050 sheets. The Al sample was compared to one FSPed sample without reinforcement and four FSPed samples with SiC reinforcement with different volume fractions added in grooves before FSP. Constant conditions of 1500 rpm for rotational speed, 116 mm min−1 for feed rate, and three number of passes using a square shape tool were applied to all samples in order to study the effect of SiC volume fraction on microstructure, mechanical properties and wear resistance within each specimen. Optical microscopic analysis (OM) in collaboration with scanning electron microscope (SEM) were used to fully discuss the microstructural changes within each sample. Mechanical and tribological properties were investigated through microhardness and tension test (including yield strength, ultimate tensile strength and percentage elongation) in addition to wear resistance test. The results show significant improvement in microstructure changes in the FSPed composites, where equiaxed and refined grains structure were obtained due to the effect of the severe plastic deformation and continuous dynamic recrystallization caused by FSP compared to the elongated and coarse grains of the base metal. Microhardness and strength of the FSPed composites improved up to 112% and 9.7% respectively compared to the as-received material. The wear resistance of the FSPed composites have improved by 62% compared to the as-received metal due to the higher surface hardness obtained due to the presence of SiC particles.