Deformation and toughness

Ektar Performance Plastic s trade name for its family of copolyester thermoplastic elastomer, elastic constant See modulus of elasticity, elastic deformation See deformation, elastic en-ergy, plastic work rheology, elastic fracture See melt fracture, elastic hysteresis See hysteresis, elastic, elasticity A property that causes plastic to return to its original size and shape after removal of a force causing deformation. See coefficient of elasticity deformation and toughness extruder-web stretching and... 

Lauke, B. Theoretical considerations on deformation and toughness of short-fiber reinforced polymers. JPolym Eng., 11,103-154 (1992). 

Film Adhesion. The adhesion of an inorganic thin film to a surface depends on the deformation and fracture modes associated with the failure (4). The strength of the adhesion depends on the mechanical properties of the substrate surface, fracture toughness of the interfacial material, and the appHed stress. Adhesion failure can occur owiag to mechanical stressing, corrosion, or diffusion of interfacial species away from the interface. The failure can be exacerbated by residual stresses in the film, a low fracture toughness of the interfacial material, or the chemical and thermal environment or species in the substrate, such as gases, that can diffuse to the interface. 

Hardness (qv), which determines the resistance of a material to abrasion and deformation, is affected not only by composition but also by porosity and microstmcture. Higher cobalt content and larger carbide grain size reduce hardness and abrasion resistance but iacrease the toughness of cemented carbides. The trade-off of abrasion resistance and toughness enables the cemented carbide manufacturer to tailor these materials to a wide variety of metal-cutting and nonmetal-cutting appHcations. 

Resistance to deformation and degradation at temperatures of the order of 250°C unmatched by any other polymer of comparable rigidity and toughness. 

Some of the important inelastic properties of a material undergoing plastic deformation are yield strength, ultimate tensile strength, ductility and toughness. 

Since it measures the susceptibility of materials to plastic deformation (as contrasted with elastic deformation), hardness is very important for diagnosing the mechanical state of a material, in particular toughness. Purely elastic materials are brittle. Plasticity, by blunting cracks and other defects, allows metals and, to some extent ceramics, to tolerate small flaws and thereby become malleable and tough. 

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