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Author Interview: Carbon Nanotubes: Reinforced Metal Matrix Composites

by Editor1 last modified February 22, 2011 - 18:36 talks with the Dr. Aravind Agarwal, of Florida International University Mechanical and Materials Engineering Department, and author of Carbon Nanotubes: Reinforced Metal Matrix Composites.

Author Interview:  Carbon Nanotubes: Reinforced Metal Matrix Composites

This research volume takes a problem-solving approach exploring the mechanisms through which CNTs are enhancing the properties of different metal-based composites, the authors provide a roadmap to help researchers develop metal matrix carbon nanotube (MM-CNT) composites and choose potential materials for use in emerging areas of technology.

Dr. Agarwal‘s intent is that the book provide researchers, manufacturers and administrators a comprehensive assessment of current and future CNT developments to help all these professionals plan and make decisions. Arvind, I know what Carbon Nanotubes are, but tell me about reinforced metal matrix composites please – and keep it light please, as I am a layman after all! How about some everyday examples of how this area is used in our society today?

Agarwal: An engineer is always in search of a new material with lower density and higher strength. The idea to reinforce metal matrix with carbon nanotubes is to obtain “composite” materials which has improved strength and stiffness but with low density. Carbon nanotubes have low density, high strength, and very high electrical and thermal conductivity. Thus, one can design multifunctional materials for a host of applications.

Although metal matrix carbon nanotube (MM-CNT), composites are still at research stage, there are several potential applications. Some examples would be light-weight automobile components (for improved fuel efficiency), satellite and aerospace components (to enable higher payloads), heat sinks in electronics (due to high thermal conductivity) and sensors (due to high electrical conductivity). Your book is full color throughout and you have some stunning photographs included – which ones should we pay close attention to and why?

Agarwal: Figures in this book are very closely integrated with the text and the related information. It is very difficult to pick few figures as all of them convey important information. However, I would emphasize on the following figures:

     1. Fig 2.1: It is an excellent summary of all the processing methods to synthesize MM-CNT composites.
     2. Fig 2.15: shows that CNT reinforced metal matrix composites can be fabricated to complex near net shapes by plasma spray forming. This is important as nano-manufacturing and scaling up is a major challenge in the field of nanotechnology.
     3. Fig 3.9: This figure provides a comprehensive characterization for MM-CNT composites.
     4. Fig 5.1: MM-CNT composites behave differently at different length scales. This figure provides important information on different models that can be used to predict strengthening and stiffening in these composites.
     5. Fig 6.5: The wetting behavior of metal on CNT surface is critical for stronger interface. This figure shows the dynamic wetting behavior of molten metal on CNT surface.
     6. Fig 7.11: presents a unique way of quantification of CNT dispersion. The dispersion of CNTs in a matrix is the most critical issue in this research area.
     7. Fig 8.13: is a very clear demonstrator of how addition of CNTs improves the wear at nano-scale length. The scratch volume decreases with the CNT addition for all loads.
     8. Fig 10.4: This is probably the most critical figure of the book as it provides the direction in which further work is needed for the success of MM-CNT composites. We thought of this figure after a comprehensive study of the subject. We strongly feel that MM-CNT community will take up some of these research challenges in near future. You are based at Florida International University in Miami. What research is going on there for nanotechnology?

Agarwal: A lot of research work is being carried out at Florida International University (FIU) in the field of nanotechnology. Apart from CNT composites, FIU is also conducting nanotechnology research in these areas:
  • Carbon nanotube based electronics, sensors and battery
  • Graphene based material for energy applications
  • Nanomechanics of biological materials and cells
  • Nanodiamond
  • Nanomedicine I’m offering close to 25,000 newsletter subscribers a sample chapter from you book. Tell us about one of your favorite sections.

Agarwal: As I mentioned earlier, nano-manufacturing and scaling up is a major challenge in the field of nanotechnology. Chapter 2 describes all the processing techniques and their limitations, as applicable to MM-CNT composites. This chapter will provide readers a thorough understanding of the roadblocks and future directions with respect to processing of MM-CNT composites. US, China, South Korea, Japan, and India have great relevance to the subject matter of carbon nanotubes – do tell, why?

Agarwal: The majority of the research on CNT is being done in these countries. US, China, South Korea and Japan are leading the research in the area of MM-CNT composites. In my private communication with collaborators and researchers in China and Japan, I have learnt that CNT composite research will get a further boost in these countries in coming years, due largely to interest in using CNTs in the automobile industry. In fact, Honda has released a document where they have shown that using CNT composites will result in a weight savings in automobiles that will result in significant energy savings. Chapter 10 of your book includes a Summary and Future Direction of this area – what can we expect to see five or ten years from now?

Agarwal: I definitely expect that researchers will be able to solve the problem of CNT dispersion. Also, they will be able to manufacture the composites with a better control. This will assist in developing more standard testing and evaluation methods, especially for mechanical properties. Speaking of CNT dispersion, one reviewer noted your book’s treatment of that area made it a standout in today’s literature. Let me quote, ”One highly critical section is the quantification of carbon nanotube dispersion in the metal matrix, which sets it apart from any other publication. This book will be a definite book on the shelf of material scientists and engineers.” Congratulations on that.

Agarwal: Thank you. What other inclusions in your book do you think will set it apart?

Agarwal: This is the first book which deals purely with “metal matrix-CNT composites”. Since this is the least researched area among all CNT composites, we have made a comprehensive attempt to include every aspect of this research.

Apart from CNT dispersion quantification, readers will find Tables in Chapter 4 to be very important for their research on a specific metal-CNT system. These tables are very comprehensive in nature and summarize processing method, composition, CNT dispersion method, and key properties. It will serve as an excellent compendium to both a new and advanced researcher in this field. There are about 25 journals that you looked very closely for your research for this area – tell us a few of your favorites and why?

Agarwal: CNT composite research is spread over several journals. But some of the key papers are published in the following journals: Carbon, Advanced Materials, Materials Science and Eng. A, Composite A, Composite Science and Technology, Surface Coating and Technology, Scripta Materialia and Acta Materialia. I routinely look at these journals for the papers in the area of MM-CNT composites. Finally, you live in Miami, and there are some terrific places to eat down there – any recommendations?

Agarwal: My picks are: Tiramisu on Lincoln Road, South Beach and Lotus Garden on Miracle Mile, Coral Gables.