Effect of Post-weld Thermal Treatment on Mechanical Properties of Welded Aluminum-Alloy Engine Head

The effect of post-weld thermal treatment has been investigated experimentally in an attempt to improve the mechanical properties of welded aluminum-alloy engine head. Welding of the locally damaged engine head is performed using two different filler metals—one is the commercial aluminum filler and the other base metal itself. Mechanical properties of the repaired engine head are analyzed before and after applying the thermal treatment in terms of measured values of micro-hardness, tensile strength, yield strength, percentage elongation at different zones of the welded samples. In order to realize the effect, microstructures of different welded samples are also observed through optical and scanning electron microscopes. Results of the present investigation show that the thermal treatment significantly improves the mechanical properties as well as microstructure of the welded region of Al-alloy engine head, especially those obtained by using the base filler metal.