High temperature fretting wear behavior of CMT-based wire arc additive manufactured AA4043 alloy

Abstract

The AA4043 is an established aluminum alloy known for its exceptional weldability, corrosion resistance, and high strength-to-weight ratio. This makes it ideal for aerospace, marine, and automobile applications where maintaining structural properties in harsh environments is essential. Wire Arc Additive Manufacturing (WAAM) via Cold Metal Transfer (CMT) provides accurate heat control and a high deposition rate, reducing thermal distortion and making it ideal for large-scale component production in a shorter time. In this study, AA4043 aluminum alloy was fabricated using WAAM, and its microstructural, mechanical, and tribological properties were evaluated. Microstructural analysis revealed a gradient in dendrite morphology across the build height, with finer dendrites observed in the top region, moderately sized dendrites in the middle, and coarser dendrites in the bottom region. X-ray diffraction (XRD) analysis confirmed that no new phases are present throughout the top, middle, and bottom regions. Vickers microhardness testing revealed that the top region exhibited the highest hardness, with values 36% and 50% higher than those of the middle and bottom regions, respectively. Fretting wear tests were conducted at room temperature and 200 °C. At room temperature, the top and middle regions demonstrated superior wear resistance compared to the bottom. Interestingly, all regions showed enhanced wear resistance at 200 °C compared to room temperature, which can be attributed to a self-healing mechanism. This behavior is primarily due to the formation of a protective aluminum oxide layer during high-temperature wear, which acts as a solid lubricant and reduces material degradation.