Loading...

Study on the Fracture Behavior of Roll-bonded Laminate and FGM Structures with Crack Divider Orientation Based on Al6061-SiC Composites

Hosseini Monazzah, Asal | 2013

743 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 44221 (07)
  4. University: Sharif University of Technology
  5. Department: Materials science and Engineering
  6. Advisor(s): Seyed Reihani, Mortez; Bagheri, Reza
  7. Abstract:
  8. Discontinuously reinforced aluminum matrix composites (DRA) are candidates as a substantial class of materials for improved strength, stiffness, and wear resistance. However, the low fracture resistance of DRA's has restricted the widespread use of these materials as structural components. Consequently, intrinsic and extrinsic mechanisms have been considered in order to enhance the damage tolerance of composite materials based on microstructural and architectural modification, respectively. The intrinsic toughening technique has shown to elevate fracture resistance to some extent; usually at the expense of reducing several other properties such as strength. The more recent approach to improve fracture behavior of DRAs is based on architectural modification which yields an optimized balance of strength and toughness based on lamination. In the present work, laminate and FGM structures were considered as an architectural modification to enhance damage tolerance of aluminum matrix composites. Doing this, three-layer samples consisting two exterior layers of Al6061-SiCp and an interlayer of Al1050 were produced by hot roll bonding. This study explored the fracture behavior of architectural structures having different interfacial bonding in the crack divider configuration. To control the interfacial adhesion, rolling strain was varried. The fracture behavior of three-layer structures and the constituent material was examined via three-point bending and impact tests. The results revealed that, while initiation toughness uprises by increasing interfacial bonding, the propagation toughness relies on the SiC content of exterior layers as well as rolling strain. At high strain rate condition, it was shown that, the impact toughness of all laminates was greater than that of the monolithic samples. It is noteworthy that, the maximum impact energy was observed in the case of un-reinforced laminate rolled five passes. The results of the experiments revealed no difference in the energy of FGMs tested in three point bending. However, the impact values exhibited notable sensitivity to the number of rolling passes, i.e. the interfacial adhesion. The impact toughness of FGM structures increased by up-rising interfacial adhesion. Threrfore it seems that the mechanisms sensitive to high rolling strain controles the impact behavior of FGM structures
  9. Keywords:
  10. Aluminum Matrix Composite ; Toughness ; Functionally Graded Materials (FGM) ; Al6061/SiCp composite ; Roll Bonding ; Laminate Structure

 Digital Object List

 Bookmark

No TOC