Influence of Microstructural Characteristics on the Mechanical and Wear Behavior of Wire Arc Additive Manufactured and Cast Eutectic Al-Si Alloy

The present study investigates the dry sliding wear behavior of Wire arc additive manufactured (WAAM) eutectic Al-Si alloy, with a particular focus on the effects of solidification and microstructural characteristics on wear behavior. Microstructural analysis indicated that the secondary dendrite arm spacing (SDAS) for the WAAM sample was three times higher than that of the cast sample. The WAAM sample exhibited thin, long columnar dendrites, while the cast samples displayed coarse and ripened dendrites. Furthermore, EBSD analysis revealed that the WAAM sample had a higher percentage (88.6%) of low-angle grain boundaries (LAGBs), contributing to their increased strength compared to cast samples with 78.6% LAGBs. The maximum wear rate of 5.45 x 10-6 g/m was observed at a normal load of 25 N and a sliding speed of 1.1 m/s with a coefficient of friction (CoF) of 0.59 for WAAM samples while casting samples exhibited a lower wear rate of 3.06 x 10-6 g/m and a CoF of 0.55 under identical conditions. Delamination, severe adhesion, and abrasion were the primary wear mechanisms under maximum wear rate test conditions. The subsurface of WAAM samples contained a mechanical mixed layer (MML), while cast samples revealed a stable thin oxide layer. The study found that samples with higher texture strength and lower Taylor factor (TF) values were more prone to damage.