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Brittleness. A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound.
Embrittlement is a significant decrease of ductility of a material, which makes the material brittle. Embrittlement is used to describe any phenomena where the environment compromises a stressed material's mechanical performance, such as temperature or environmental composition. This is oftentimes undesirable as brittle fracture occurs quicker ...
Crystallization of polymers is a process associated with partial alignment of their molecular chains. These chains fold together and form ordered regions called lamellae, which compose larger spheroidal structures named spherulites. [1][2] Polymers can crystallize upon cooling from melting, mechanical stretching or solvent evaporation.
Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversible upon removing the stress. Ductility is a critical mechanical performance indicator, particularly in ...
Polymer characterization is the analytical branch of polymer science. The discipline is concerned with the characterization of polymeric materials on a variety of levels. The characterization typically has as a goal to improve the performance of the material. As such, many characterization techniques should ideally be linked to the desirable ...
Crazing. Crazing is a yielding mechanism in polymers characterized by the formation of a fine network of microvoids and fibrils. [1][2] These structures (known as crazes) typically appear as linear features and frequently precede brittle fracture. The fundamental difference between crazes and cracks is that crazes contain polymer fibrils (5-30 ...
Crazes (surface cracks) produced by ESC in PMMA drinking beaker. Environmental Stress Cracking (ESC) is one of the most common causes of unexpected brittle failure of thermoplastic (especially amorphous) polymers known at present. According to ASTM D883, stress cracking is defined as "an external or internal crack in a plastic caused by tensile ...
Fracture in polymers. Polymer fracture is the study of the fracture surface of an already failed material to determine the method of crack formation and extension in polymers both fiber reinforced and otherwise. [1] Failure in polymer components can occur at relatively low stress levels, far below the tensile strength because of four major ...