Abstract
Compared to traditional ceramic reinforcements, metallic particles have emerged as effective reinforcements for simultaneously enhancing the strength and ductility of magnesium alloys. In this study, a high-entropy alloy (HEA) was introduced as a reinforcement, and a novel magnesium-based composite with 1.5 vol.% AlCoCrFeNi particles was fabricated using the thixomolding technology. The AlCoCrFeNi/AZ91D composite achieves a well-balanced combination of mechanical properties, with a yield strength of 182.8 MPa, an ultimate tensile strength of 280.3 MPa, and an elongation of 6.1 %. The deformation mechanisms of the composite were systematically analyzed through in-situ X-ray diffraction and full-field crystal plasticity (CP) simulation. The results reveal that the AlCoCrFeNi particles effectively bear the applied load throughout the entire deformation process, without cracking or interface debonding. The matrix/particle interface exhibits a distinct nanoscale production layer, which contributes to a strong interfacial bonding. The edges of the AlCoCrFeNi particles adjacent to the magnesium matrix undergo plastic slip, which helps accommodate interface heterogeneous deformation and improve ductility. According to the CP simulation, the von Mises stress in the AlCoCrFeNi particle interior is approximately 700 MPa, while it exceeds 1200 MPa at the edges. Higher stress at the particle interface and the soft interfacial layer fundamentally drive the plastic flow. Furthermore, the AlCoCrFeNi particles experience unidirectional or multidirectional compressive stress, which enhances particle toughness and inhibits cracking. This study proposes a new strategy for developing lightweight metal composites, leveraging the low density of magnesium alloys and the high strength of body-centered cubic HEA reinforcements.
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