Influence of TiO2 nanoparticles incorporation to friction stir welded 5083 aluminum alloy on the microstructure, mechanical properties and wear resistance

Abstract

The aim of the current study is to investigate the effect of addition of TiO2 nanoparticles and friction stir welding (FSW) parameter such as number of passes on microstructure, mechanical and tribological properties of friction stir butt-welded joints of AA5083 alloy plates. The experiments were performed on AA5083 alloy based composite plates at different rotational and forward speed in the range of 300-710 rpm and 14-28 mm/min respectively. The optimized high strength value based AA5083/TiO2 composite plates were then subjected to different number of passes ranging from 1 to 4. These butt-welded regions of TiO2 reinforced and unreinforced AA5083 alloy plates were characterized using optical and scanning electron microscope (SEM) to study the microstructure, dispersion of TiO2 and grain size. The hardness and ultimate tensile strength of AA5083 composite after four passes with rotational speed of 710 rpm and forward speed of 14 mm/min was increased by 40% and 25% when compared to that of unreinforced AA5083 alloy. The wear characteristics of all butt-welded samples evaluated using pin on disc tribometer revealed better wear resistance and low friction coefficient for samples processed using four numbers of passes. The fractured tensile samples and worn out surfaces after wear testing were analyzed through SEM. The improvement in mechanical and wear properties are mainly attributed to reduced grain size, uniform dispersion of TiO2 nanoparticles and dislocation strengthening.