Effect of Rotational Speed on Wear Behavior and Mechanical Properties of Friction Stir Welded AA۶۰۶۱+۱۵%Al۲O۳p Metal-Matrix Composite

The main objective of the present work was to investigate the effect of tool rotational speed on the mechanical and microstructural properties of aluminum based metal matrix composites (AA ۶۰۶۱ alloy reinforced with ۱۵% of Al۲O۳ particles). The welds were produced by varying the rotational speed from ۶۳۰ to ۱۲۵۰ r/min while the chosen welding speed was ۸۰ mm/min for analysis. It was found from the analysis of the microstructure that the changing of the rotational speed leads to variation of the grain size and also the fragmentation and improvement of Al۲O۳ particles distribution in nugget zone. Moreover, the obtained results clearly depicted that increasing rotational speed from ۶۳۰ to ۱۲۵۰ r/min resulted in improvement of the wear resistance and also decreases the fluctuations of friction coefficient which can be attributed to the presence of Al۲O۳ particles which acted as barriers and restricted the grain growth in nugget zone. The lowest wear rate was achieved at welds produced at rotational speed of ۱۲۵۰ r/min. It was seen from the hardness results that the highest tensile strength value was obtained for ۱۲۵۰ r/min rotational speed with an average value of about ۳۲۰ MPa (equivalent to ۸۲% that of the base metal).

کلیدواژه ها:

Friction Stir Welding ، Metal matrix composite ، Rotational Speed ، Tensile strength ، wear resistance