Microstructure, mechanical properties and thermal conductivity of the short carbon fiber reinforced magnesium matrix composites

Abstract

The short carbon fibers reinforced magnesium matrix composites were prepared with powder metallurgy technology. The microstructure, mechanical properties and thermal conductivity of the materials were investigated. Results show that, when the short carbon fibers without coating are used, there exist obvious defects at the interface between reinforcement and matrix. After nickel plating, there exist the phases of Ni3P and Mg2Ni at the interface between the short carbon fibers and magnesium matrix. The coating increases the interface wettability between matrix and short carbon fibers. Therefore, the mechanical properties of the composites are improved. When the content of short carbon fibers is 1.0 vol%, the composite possesses a good combination of mechanical properties and thermal conductivity with a hardness of 65.3 HV, a compressive strength of 169.0 MPa and a thermal conductivity of 120.6 W/m·K. In the same specimen, thermal conductivity in the direction of horizontal is higher than that in the direction of vertical.