Deformation and Fracture Behavior of Alumina Particle-Reinforced Al 6061-T6 Composite during Dynamic Mechanical Loading
- PDF / 722,775 Bytes
- 7 Pages / 593.972 x 792 pts Page_size
- 88 Downloads / 227 Views
I.
INTRODUCTION
THE high specific strength and specific stiffness of aluminum-based metal matrix composites (AMCs) coupled with their excellent oxidation and corrosion resistance encourage their use in the automobile and aerospace industries. They are currently considered as candidate materials for advanced structural armour.[1] In many of the aforementioned applications of AMCs, the chances of exposure to deformation at high strain rates are high. Their response to dynamic loading is therefore an essential design parameter that is critical for an enhanced performance and reliability in service. Investigations have shown that metal matrix composites are more prone to dynamic loading effects than their corresponding monolithic materials.[2] Thermomechanical instability due to thermal softening controls, to a large extent, the deformation and failure mechanism in metallic materials at high strain rates. Heat generated during deformation accumulates along certain narrow bands resulting in extensive thermal softening and shear strain localization along the narrow bands. These narrow bands of extreme shear strain localization are A.G. ODESHI, Research Associate, M.N.K. SINGH, Assistant Professor, and M.N. BASSIM, Professor, are with the Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, MB, Canada R3T 5V6. Contact e-mail: odeshiag@cc. umanitoba.ca G.M. OWOLABI, Postdoctoral Research Fellow, formerly with the Department of Mechanical and Manufacturing Engineering, University of Manitoba, is Visiting Research Scholar, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, USA. This article is based on a presentation made in the symposium entitled ‘‘Dynamic Behavior of Materials,’’ which occurred during the TMS Annual Meeting and Exhibition, February 25–March 1, 2007 in Orlando, Florida, under the auspices of The Minerals, Metals and Materials Society, TMS Structural Materials Division, and TMS/ASM Mechanical Behavior of Materials Committee. Article published online July 14, 2007 2674—VOLUME 38A, NOVEMBER 2007
called adiabatic shear bands. Formation of adiabatic shear bands at high strain rates leads to a decrease in shearing stresses that can be transmitted through a material and cause failure.[3–6] Initiation and propagation of adiabatic shear bands (ASBs) are influenced by material and test parameters such as heat conductivity, heat capacity, strain rate sensitivity, strain rate, microstructure, and specimen geometry, among others.[4,5] Feng and Bassim[7] observed that ASBs cannot form without the presence of material or geometrical defects. Shonefeld and Wright[8] also observed that shear strain localization is promoted by inhomogeneity in the microstructure. For AMCs, the inherent inhomogeneity, as a result of particulate reinforcement, can cause nonuniform plastic deformation and thus enhance the tendency for shear strain localizations due to thermomechanical interactions.[9] Perng et al.[10] noted that the ultimate tensile str
Data Loading...
