ABSTRACT
Several metal matrices have been reinforced with carbon nanotubes in order to study the feasibility of composite fabrication and their properties for potential applications. Figure 1.5 in Chapter 1 showed the pie chart of the percentage of publications on various metal matrices. Based on the number of total articles published in journals, it is observed that Ni-CNT composites have been researched the most for non-structural applications whereas Cu-CNT and Al-CNT composites have received major attention for structural applications. Other matrices like Mg, Ti, and Si have also received some attention. Attempts have also been made to incorporate CNTs in novel materials like metallic glasses. The aim of this chapter is to provide the reader an idea of the various attempts made by researchers in the area of MM-CNT composites. In this chapter, we look into specific metal-CNT systems and summarize the majority of the work carried out to date. This work has been summarized in the form of exhaustive tables (Tables 4.1-4.6) for each metal-CNT system. These tables list important information for each metal-CNT system such as: (1) composite processing technique, (2) CNT dispersion method used, (3) CNT content and quality of dispersion, (4) reaction at the CNT/matrix interface, if any, and, (5) material properties. Since the largest intended application of the MM-CNT composites is for structural purposes, most of the researchers have reported the mechanical properties of these composites. Hence, mechanical properties (elastic modulus, hardness, yield/tensile strength, strain to failure) of MM-CNT composites are also tabulated to highlight the role of CNT addition. It was discussed in Chapter 3 that mechanical testing and properties are highly dependent on the processing methods, which often dictates the shape and dimensions of the test samples made out of MM-CNT composites. The samples utilized for the mechanical property evaluation are often non-standard in size. The sample size used to evaluate the mechanical properties of the metal matrices with and without CNT reinforcements is also outlined in Tables 4.1-4.6. These tables include a separate column that outlines the improvement in other properties, namely, electrical, thermal, tribological, etc. A detailed discussion on the improvement of other properties such as wear, thermal, and electrical properties is provided in Chapter 8. A short discussion for each MM-CNT composite system is also included to highlight the most significant studies related to the mechanical properties. This chapter also provides the reader a clear understanding of the MM-CNT composites with the scope for further research.
