ABSTRACT
Fracture toughness is an important consideration in determining substances which can be cryopulverized efficiently. Impact-testing is one of the most common methods to measure fracture toughness. This chapter shows qualitatively how fracture toughness of typical materials changes as a function of temperature. The brittle temperature measurement is also subject to how fracture toughness is measured. Crystallinity can have an enormous influence on the fracture properties of a polymer. Normally the higher the polarity of the material, the more difficult it is to fracture. Additives can have a profound influence on the fracture toughness of a polymeric material. The fracture toughness of copolymers and terpolymers is strongly dependent on the types of monomers used and their relative percentages in the material. As with polymers, metals exhibit decreases in fracture toughness with increasing stress or strain rate. For iron-based steels, fracture toughness is increased by the addition of such elements as aluminum, titanium, and zirconium.
