A national workshop organized Indian Institute of Metals

New Horizons in Metallurgy, Materials, and Manufacturing

A national workshop organized by Indian Institute of Metals
December 14th - 16th 2020

Home Schedule Speakers

Composite Materials: An Overview and Recent Advances

avatar Prof. Rakesh K. Gautam
  • Bio

    Rakesh Kumar Gautam is Associate Professor of Mechanical Engineering, IIT (BHU), Varanasi, India. He completed his B. Tech., from Madan Mohan Malviya Technical University, Gorakhpur (1999), M.Tech. from Institute of Technology (2001) presently Indian Institute of Technology (BHU) Varanasi and PhD from Indian Institute of Technology Roorkee (2009). He has nearly 14 years of teaching experience at IIT (BHU). His area of teaching is machine design like engineering Mechanics, Machine Designs, Strength of materials, Mechanical Measurement, Composite Materials, Tribology etc. He is working in the area of development of different types of composites, alloys and their physical, mechanical and tribological properties for various applications. Also, working in the field of microwave sintered composites, Bio-tribology, Dental tribology etc. He has credited to various publications in refereed Journals likes ASME, Wear, Tribology International, Materials and Design, Ceramic International etc. He is reviewer of several international journals like ASME, IMeche etc. He has produced several M. Techs. and guiding PhDs students. He is also life member of Tribological Society of India. Currently, running a DST sponsored project on dental tribology.

  • Abstract

    When two or more constituent materials are combined on a microscopic scale it results in a composite material whose physical properties are very different than the properties of the constituents due to their synergy. In composites when the reinforcing phase is synthesized within the matrix during fabrication it is called in-situ composite. This contrasts with ex-situ composites where the reinforcing phase is synthesized separately and then integrated during composite fabrication by solidification processing or powder metallurgy route. Because of the formation of ultra fine and stable ceramic reinforcements, the in-situ MMCs are found to exhibit excellent properties.

    When different kinds of reinforcements (particulates, fibres etc.) is added into a single matrix, resulting a hybrid composites. In hybrid composites, matrix may be of metal, polymer, ceramic and carbon. The hybrid composite which has two or more kinds of reinforcement, the benefit of one type of reinforcement could complement with what are lacking in the other. These hybrid composites show a better performance with an optimum cost (Jacob et al., 2004).

    A nano composite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nano meters (nm), or structures having nano scale repeat distances between the different phases that make up the materials. In the broadest sense this definition can include porous media colloids, gel and copolymers, but is more usually taken to mean the solid combination of a bulk matrix and nano dimensional phases differing in properties due to dimensional in structure and chemistry.

    Aluminium matrix composites (AMCs) refer to the class of light weight high performance aluminium centric material systems. The reinforcement in AMCs could be in the form of continuous/discontinuous fibres, whisker or particulates, in volume fractions ranging from a few percent to 70%. Properties of AMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. Presently several grades of AMCs are manufactured by different routes. In the last few years, AMCs have been utilised in high-tech structural and functional applications including aerospace, defence, automotive, and thermal management areas, as well as in sports and recreation.

    However, in the 1990s a new field of artificial self-healing materials has emerged. These materials, inspired by the ability for selfhealing in biological objects, are designed in such a way that they include mechanisms that can at least partially repair damage, such as voids and cracks, and partially or completely restore macroscopic material properties. Usually, a healing agent (often a liquid) is stored in the matrix of the material and when a cavity (a crack or void) is formed, it fills the cavity and closes it due to a chemical reaction or a phase transition (e.g., solidification). The healing can be autonomous (without human intervention) and non autonomous. The latter require some external intervention, such as heating the material to trigger the repair process (Ghosh 2009; Zwaag 2007).

    We live in an interesting time for materials scientists and engineers, when new advanced technology gives us the ability to control structure and properties at the micro- and nanoscale, and when new experimental discoveries in biology give us the insight of how materials and tissues in living nature achieve their remarkable properties. At this interface, the new fields of advanced, nanostructured, smart, functional, and biomimetic materials have emerged.