Microstructure, hardness, and tribological properties of AA2014 powder metallurgy alloys: A sizing mechanical surface treatment study

• Sizing mechanical surface treatment significantly affects tribological performance. • Low-pressure sizing leads to high dislocation density around porosities, causing delamination. • Higher sizing pressure promotes uniform misorientation and improved wear resistance. • A uniform oxide tribolayer was observed in as-sintered samples. This study explores the influence of sizing mechanical surface treatment on the tribological response of AA2014 powder metallurgy (PM) alloy-steel tribosystem under reciprocating sliding wear. The impact of sizing pressure on wear mechanisms is analyzed using a combination of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), surface topography, hardness testing, wear rate measurements, and microscopic analyses. The results show that sizing treatment can significantly alter wear mechanisms, shifting from abrasion and mild oxidative wear to delamination and cracking, especially at lower sizing pressures. Samples sized at 200 MPa and 300 MPa displayed pronounced delamination and cracking. In contrast, increasing the sizing pressure to 400 MPa enhanced mechanical properties, reduced the wear rate, and minimized delamination. This suggests that although sizing with relatively low sizing pressure can increase hardness, it may detrimentally affect the alloy’s wear performance by intensifying stress concentration effect. However, wear properties benefit from the superior mechanical properties gained through cold working of the alloy at a higher pressure of 400 MPa. This research highlights the critical role of sizing pressure in optimizing the tribological performance of sized aluminum PM alloys.