Circumferential tribological behavior of powder-metallurgy processed B4C-reinforced aluminum matrix composites at room and elevated temperatures

Although B 4 C-reinforced aluminum matrix composites have attracted considerable attention, the high-temperature tribological behavior of B 4 C/7xxx series aluminum alloy composites has rarely been explored, greatly limiting their potential applications in thermally demanding service environments. To address this gap, a 15 wt.% B 4 C/7093Al composite was fabricated via powder metallurgy followed by hot extrusion, and its circumferential sliding wear behavior was systematically investigated over the temperature range from room temperature (RT) to 500 °C. The results revealed a pronounced temperature-driven transition in the dominant wear mechanisms: from RT to 400 °C, abrasive wear gradually shifted toward a synergistic mechanism involving oxidative wear and delamination, while oxidative wear became predominant at 500 °C. Overall, both the coefficient of friction and the volumetric wear rate decreased with increasing temperature. Notably, under a low rotational speed of 100 rpm, the friction coefficient exhibited a maximum reduction of 19.6%. The synergistic effect of elevated rotational speed and applied load further amplified the reduction in wear rate, leading to a total decrease of 25.3% under the 200 rpm–20 N condition. Furthermore, subsurface microstructural analysis of the wear tracks revealed significant temperature-induced plastic deformation features. This work not only deepens the understanding of high-temperature wear failure mechanisms in B 4 C/7093Al composites, but also provides valuable data to support the design and application of key components and tribo-pairs for extreme-service environments such as aerospace, transportation, and nuclear energy systems.