Mechanical characterization of Al/Ti-6Al-4V surface composite fabricated via FSP: A comparison of tool geometry and number of passes

Aluminium alloys specifically the 1100 grade are used majorly in the manufacturing industries. However, the alloy experiences wear while being used which in turn causes reduction in the service life of this alloy. One of the most common causes of failure in aluminum alloy is wear and with the aim to improve the wear resistance of this aluminum alloy, friction stir processing (FSP) was used to fabricate the surface composite of the Al/Ti-6Al-4V system. The Ti-6Al-4V particles were mixed into the 1100 Al alloy by employing two (2) different tool geometries (i.e., square shape and threaded taper) with a varying number of passes from 1-3 passes and a varying tool rotational speed of 600 and 1200 rpm. The results of this study showed that the tool shape, tool speed and the number of passes play significant role in the distribution of the reinforcing particles, which consequently affect the hardness, microstructural modifications, tensile properties and wear performance of these composite samples. The highest wear resistant composite was attained with threaded taper tool with 3 passes at 1200 rpm. Furthermore, the composite realized a wear resistance of 50% increment and a 40% reduction in friction coefficient compared to the 1100 Al alloy, this composite consequently exhibits the highest hardness and strength.