Preparation and mechanical properties of carbon fiber reinforced Mg-4Y-2Nd-1Gd-0.5Zr composite with in-situ formed triple-layer interface

Carbon fiber reinforced magnesium matrix composite (CFRMMC) was fabricated using two-dimensional orthogonal laminated (TOL) carbon fiber and Mg-4Y-2Nd-1Gd-0.5Zr (WE43) alloy. Microstructural characterization revealed an in-situ formed triple-layer interface because of the addition of Zr and rare earth (RE) elements. This interfacial structure apparently enhanced the bond between carbon fiber and matrix, and facilitated effective stress relaxation and stress transfer under external loading. To benefit from this optimized interface, the fabricated composite exhibited exceptional mechanical properties combined with high modulus and thermal conductivity, achieving an ultimate tensile strength (UTS) of 640.9±7.0 MPa, elastic modulus (E-mod) of 338.1±1.9 GPa, and thermal conductivity coefficient of 376.156 W m⁻¹ K⁻¹. Furthermore, a modified rule of mixtures for the TOL-CFRMMCs was developed by incorporating the effects of thermal mismatch and interfacial layers, reducing the theoretical prediction error of UTS from 165.1% to within 0.58%, which further demonstrated the effectiveness of the synergistic effect between Zr and RE elements at the theoretical calculation level.