FRACTOGRAPHY OF WASPALOY WIRE DEPOSITED WITH LASER AND ARC ADDITIVE MANUFACTURING PROCESSES

Abstract

Welding with filler material can be considered as an additive manufacturing process whereby it involves the deposition of molten metal in a form of droplets onto a substrate. Wire and Arc Additive Manufacturing (WAAM) and laser direct metal deposition (DMD) are applied for repair purposes, hard facing, and building structures in various industries such as the aerospace industry. In this research, High-Powered Diode Laser (HPDL) and Gas Tungsten Arc Welding (GTAW) were used as the heat sources to deposit Waspaloy wire layer-by-layer to form a thin wall. The heat flow during the deposition process causes a change in the microstructural and mechanical properties of the subsequent layers. Following the deposition process, solution treatment and aging heat treatment were performed on the Waspaloy thin wall. Understanding the process/property relationship is crucial to ensure the reliability of the built structure. Tensile testing was performed prior to fractography. Fractography is critical to the failure analysis of metals. The objective of this research is to study the microstructure at the fracture surface of wrought Waspaloy, as-deposit, and the heat-treated thin wall, in which it was observed by using a scanning electron microscope (SEM). Fracture surfaces of samples tested transverse and parallel to the deposition height show major difference. SEM fractography revealed an intergranular failure in the wrought Waspaloy. The laser and arc deposited Waspaloy both show fractures by microvoid coalescence initiated by interdendritic particles. Fractography analysis in this research has effectively employed to identify the fracture origin, failure mechanism, material defects, and the nature of stresses.