High Strength Magnesium Matrix Composites Reinforced with Carbon Nanotube
Shinshu University Japan
It has been increasingly important to develop lightweight and high-strength materials for improving energy-efficiency through the weight reduction of transportation carriers. Magnesium alloys have attracted lots of attentions[1-3], since the density of magnesium is approximately two thirds of that of aluminum and one fifth of steel. As a result, magnesium alloys offer a very high specific strength among conventional engineering alloys. In addition, magnesium alloys posses good damping capacity, excellent castability, and superior machinability. However, compared to other structural metals, magnesium alloys have a relatively low mechanical strength, especially at elevated temperature. The need for high-performance and lightweight materials for some demanding applications has led to extensive efforts in the development of magnesium matrix composites and cost-effective fabrication technologies. They are proved to have good mechanical properties through an incorporation of structural filler (e.g., ceramic whiskers such as silicon carbide whisker and others, aluminum oxide, graphite and other particles, carbon fibers and carbon nanotubes: CNTs) [4-7]. Within this context, the dimensionally nano-sized, mechanically strong CNTs [8-11], considered as the ideal reinforcing filler in various composite systems [12-15], have been incorporated into magnesium matrix [16-19]. This chapter put the spotlight into the very attractive new magnesium alloy matrix composites reinforced with CNTs.
2. Processing techniques for fabricate the metal matrix composite (MMC) with CNTs
The reinforcing phases such as powders, fibers and whiskers are generally incorporated into the metal matrices mostly by two typical techniques of liquid state fabrication and solid state fabrication [3,20]. The key techniques in the processing of MMC are how to realize...