Effect of Boron carbide and Silicon carbide reinforced particles on the mechanical and metallurgical properties of friction stir welded joints of AA-6063 alloy

Abstract

Friction Stir Welding (FSW) is a solid state joining process. It is used worldwide, especially in automobile
defense and aerospace industries. Welding of similar and dissimilar aluminium alloy exhibits poor weld ability by fusion
process. Friction stir welding is a technique in which the material that is being welded does not melt and recast. The welding
parameters such as tool rotational speed, welding speed and tool pin profile plays an important role in deciding the weld
quality. In the present study, an attempt is made to weld the AA6063 plates by doping SiC and B4C reinforced particles in
welding zone during FSW. The selected material was Friction stir welded at constant tool rotational and welding speed of
1600 rpm and 60 mm/min respectively. High chrome high carbon non-consumable cylindrical left handed thread pin profile
tool with 4.8 mm pin length and 6 mm pin diameter was used to generate frictional heat and plastic deformation. B4C and
SiC particles are doped in a series of holes at the interfaces of plates to be joined to modify the properties of joint. The
mechanical and metallurgical properties of welded joint were investigated. From results it was observed that by doping
reinforced particles tensile strength and micro hardness improved as compare to joint welded without using reinforced
particles. Boron carbide provides better results as compare to silicon carbide. Doping of B4C and SiC particles deteriorates
the impact strength. Dispersion of B4C and SiC particles during Friction Stir welding causes grain refinement in welded
joints.