Enhancement of Mechanical Properties on Novel Friction Stir Welded Al-Mg-Zn Alloy Joints Reinforced with Nano-SiC Particles

Abstract

Friction stir welding (FSW) is a solid-state technique used to join Al-Zn-Mg alloys effectively compared with other conventional welding methods. Al-Zn-Mg alloy was processed for welding because they significantly demanded various engineering applications. A novel method of this research work is to characterize the unique mechanical properties of Al-Zn-Mg alloy reinforced with 1 to 3 wt% of nano silicon carbide (nano-SiC) particles developed by novel interlock friction-stir welding. The process parameters chosen for welding are rotational tool speed 1100 rpm, weld speed 25 mm/min, and triangular pin profile. The weld joint properties such as tensile strength, yield strength, and hardness were tested per ASTM standard. The microstructure of weld joints was studied with XRD and optical and scanning electron microscopy. The existence of silica particles in the weld joints and uniformed and homogeneous distribution of the particulates in the weld was verified by EDS analysis and microstructure. Al-Zn-Mg reinforced with nano-SiC joints has better static properties due to intensive softening in the stir region. Al-Zn-Mg with 3 wt% nano-SiC exhibits maximum tensile strength, yield strength, and nugget hardness of 191 MPa, 165 MPa, and 171 HV. Weld microstructures showed a pinning mechanism because nano-SiC particles were used as reinforcement during friction stir welding.