Interface Characteristics and Dynamic Compression Behaviors of Al35Ti15Cr20Mn20Cu10 High‐Entroy Alloy/6061Al Composites Fabricated by Spark Plasma Sintering

Abstract

Lightweight high‐entropy alloys (LWHEAs) become the research hotspot and are ideal reinforcement materials for aluminum matrix composites (AMCs). The 0, 5, and 10 vol% lightweight Al35Ti15Cr20Mn20Cu10 HEA/6061Al (HEA/Al) composites are fabricated by spark plasma sintering (SPS). The HEA–Al interfacial characteristics, dynamic compression behaviors, and failure mechanism of the composites are studied. Results show that Al35Ti15Cr20Mn20Cu10 LWHEA possesses body‐centered cubic (BCC) and face‐centered cubic (FCC) dual‐phase structures. The interfacial diffusion layer of HEA/Al is characterized as α‐Al (FCC phase) dissolved by Cr, Mn, and Si atoms, with a thickness of about 0.6 1. During dynamic compression, the introduction of Al35Ti15Cr20Mn20Cu10 LWHEA particles significantly improves the strain‐rate sensitivity of 6061Al alloy. Among them, the strain‐rate sensitivity coefficient of 10 vol% HEA/Al composites is 0.02, about four times that of the aluminum alloy matrix. Different from the micro‐failure controlled by interfacial‐debonding for AMCs reinforced by ceramic particles, the failures of HEA/Al composites are dominated by the breakage of LWHEA particles and micro‐cracks formed in the matrix, while interfacial‐debonding is rarely observed in the diffusion layers. It is concluded that a strong‐binding HEA–Al interface can effectively restrain the rapid propagation of cracks in the composites suffered by impact load.