Investigation on tungsten inert gas welding of in situ Al-15 and 20 Mg 2 Si composites with an Al-Si filler

Abstract

The feasibility of joining an in situ Al-Mg₂Si composite through the process of tungsten inert gas welding is investigated in this study. The study uses an in situ metal matrix composite reinforced with two different particulate percentages, namely 15 wt.% and 20 wt.% Mg₂Si. Welding current was adjusted at five different values between 80 and 100 amp. When joint integrity was examined under an optical microscope, three areas distinct from the parent metal were identified in the weldment region. Tension and micro-hardness tests were subsequently performed to determine the mechanical properties of the joints. The results of the micro-hardness tests correlate with those of the microstructural analyses. Joints welded with a welding current in the range of 80–85 amp displayed the highest degree of micro-hardness, with the low heat input even providing higher weld strength and integrity. The fracture produced in the welded specimens was in the base metal matrix composite, indicating a strong interface between the base metal matrix composite and the weld. It can be concluded that the tungsten inert gas welding process is very promising for the welding of in situ Al-Mg₂Si metal matrix composites.