Microstructure and mechanical properties of carbon nanotube-reinforced ZK61 magnesium alloy composites prepared by spark plasma sintering

Abstract

Abstract Monolithic ZK61 magnesium alloy and carbon nanotube (CNT)-reinforced ZK61 matrix composites were successfully prepared via spark plasma sintering. The effects of the sintering temperature on the microstructure and mechanical properties of monolithic ZK61 were studied, and the microstructural and mechanical properties of CNT/ZK61 composites were investigated as functions of the CNT content. The grain sizes of the CNT/ZK61 composites are smaller and more homogeneous than those of the monolithic ZK61 powder, and the width of the grain boundary is greater than those present in ZK61. The Vickers hardness and compressive yield strength of the CNT/ZK61 composites are observed to initially increase with increasing CNT content, reaching a maximum at 1.5 wt.% CNT, however, these values begin to decrease as the content increases further. We believe that this is owing to the grain refinement effect and load transfer mechanism of the CNT.