Tribological Behavior of AlCoCrFeNi High‐Entropy Alloy Particle Reinforced Aluminum Matrix Composites at Room and Cryogenic Temperature: Synergistic Effects of Reinforcement Content

Spark plasma sintering was employed to prepare AlCoCrFeNi high‐entropy alloy particle reinforced aluminum matrix composites (HEAp/AMCs) with varying HEAp fractions of 1–9 wt%, whose tribological and wear behaviors as well as the underlying wear mechanisms at room temperature and cryogenic temperature were investigated. Results showed that the wear resistance of HEAp/AMCs first increased and then decreased with increasing HEAp content, and the cryogenic condition further enhanced the antiwear performance of all specimens. The cryogenic enhancement was more significant for medium‐ and high‐HEAp composites. The 5 wt% HEAp/AMCs exhibited the minimum wear rate of 0.753 × 10 −3 mm 3 /Nm, a 16.1% decrease from the room temperature value. Remarkably, mechanical mixed layer and transfer layer formed at the friction interface. Cryogenic condition enhanced their structural stability, allowing them to effectively lubricated the sliding process. These findings revealed a synergistic enhancement of wear resistance by HEAp content and cryogenic condition, expanding the application potential of HEAp/AMCs as lightweight materials for extreme environments.