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Determining Mechanical Properties of Particulate Metal Matrix Nanocomposites by Numerical Method

Rezaei Mianroodi, Jaber | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42384 (08)
  4. University: Shari University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Naghdabadi, Reza; Sohrabpour, Saeed
  7. Abstract:
  8. Using materials with better mechanical properties is always advantageous. Many sectors, including automotive and aerospace industries, are always seeking new materials with better mechanical properties and lower weight. A lighter vehicle means lower emission and higher fuel efficiency. Thus, developing new methods to investigate novel materials is very important. One of these novel materials are Metal Matrix NanoComposites (MMNCs). MMNCs are fabricated using nano scale particles embedded in metallic matrix. High strength, stiffness, and hardness are the three most important mechanical properties of MMNCs. Introducing a suitable way of modeling these materials is important since it will reduce the cost of experimenting and producing specimen. There are different parameters affecting mechanical properties of the MMNCs including grain boundaries, dislocations, residual stress and particle clustering. In this thesis, two different approaches are employed to investigate mechanical properties of MMNCs. In the first stage, MMNCs are modeled using classical continuum theory with neglecting the atomic effects. Since, there are well developed Finite Element (FE) software packages based on the classical continuum theory, we have used a commercial FE package in this stage. Employing unit cell concept, about 120 2D axisymmetric and 120 3D randomly generated models are simulated both in elastic and plastic regions. Studying the resulted stress-strain curves, it is seen that the dependence of the elastic behavior of MMNCs on the particle clustering is weak. However, the dependenc of the plastic properties on the particle clustering is noticeable. In the second stage, atomic structure of the metallic matrix and the carbon based reinforcing particles are modeled using appropriate interatomic potentials. In order to perform simulations on this scale, a software is developed with implementing Embedded Atomic Method (EAM), Lennard-Jones and modified Morse potentials in FEM framework. Using this software, effects of particle volume fraction as well as the particles type on the yield stress and the Young modulus is investigated. The considered carbon-based particles are C48, C60, C70, C100 and C180. Based on the results, it is shown that adding C70 to the aluminum lattice will improve the Young modulus about while adding C48 and C100 will lower the Young modulus of the nanocomposite by and , respectively. In addition, it is shown that increasing the volume fraction of C60 particles from to will increase the Young modulus of the nanocomposite from to
  9. Keywords:
  10. Metal Matrix Nanocomposite ; Numerical Analysis ; Mechanical Properties ; Finite Element Method ; Embedded Atomic Method (EAM)Potential

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