page_title: Brittleness
hierarchical_section_title: Brittleness
caption_attribution_description: Fractured tensile test specimen of a nodular graphite cast iron. This specimens failed by brittle failure, as seen from the lack of plastic deformation. Note that nodular graphite cast irons are usually ductile, so this specimen is not representative for this class of alloys.
context_page_description: A material is brittle if, when subjected to stress, it breaks 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 snapping sound. Brittle materials include most ceramics and glasses and some polymers, such as PMMA and polystyrene. Many steels become brittle at low temperatures, depending on their composition and processing.
  When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof is to match the broken halves, which should fit exactly since no plastic deformation has occurred.
  When a material has reached the limit of its strength, it usually has the option of either deformation or fracture. A naturally malleable metal can be made stronger by impeding the mechanisms of plastic deformation, but if this is taken to an extreme, fracture becomes the more likely outcome, and the material can become brittle. Improving material toughness is, therefore, a balancing act.
context_section_description: A material is brittle if, when subjected to stress, it breaks 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 snapping sound. Brittle materials include most ceramics and glasses (which do not deform plastically) and some polymers, such as PMMA and polystyrene. Many steels become brittle at low temperatures (see ductile-brittle transition temperature), depending on their composition and processing.
  When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof is to match the broken halves, which should fit exactly since no plastic deformation has occurred.
  When a material has reached the limit of its strength, it usually has the option of either deformation or fracture.  A naturally malleable metal can be made stronger by impeding the mechanisms of plastic deformation (reducing grain size, precipitation hardening, work hardening, etc.), but if this is taken to an extreme, fracture becomes the more likely outcome, and the material can become brittle.  Improving material toughness is, therefore, a balancing act.
caption: Brittle fracture in cast iron tensile testpieces
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