Combination of enhanced thermal conductivity and strength of MWCNTs reinforced Mg-6Zn matrix composite

In this study, the multi-walled carbon nanotubes (MWCNTs) reinforced Mg-6Zn matrix composite was fabricated via powder metallurgy followed with aging treatment, and the thermal as well as mechanical properties of the composite were evaluated. Microstructural characterization revealed that MWCNTs were uniformly distributed in the composite, and a partially inserted (PI) interface was found between Mg matrix and MWCNTs. After aging treatment, a large number of β1′ phases, which had a high coherent relationship with Mg matrix, precipitated and greatly weakened the lattice distortion of Mg matrix. Besides, MWCNTs restrained the growth of the β1′ phase and refined it during aging process. The property evaluation indicated that the thermal conductivity, tensile yield strength and ultimate tensile strength of the Mg-6Zn/0.4MWCNTs composite after aging were 140.7 W/(m·K), 267 MPa and 342 MPa, respectively, showing 17%, 47% and 20% increasing in comparison with those of Mg-6Zn alloy. The significant enhancement of thermal and mechanical properties were mainly attributed to the uniformly distributed MWCNTs with strong PI interface and the MWCNTs induced regulated precipitation of β1′ phase. © 2020 Elsevier B.V.