Töréspont

Töréspont, or fracture point, is the point on a material’s stress–strain response at which it fails and breaks under an applied load. It marks the end of the material’s ability to sustain further load in a given test, and is typically determined in standard mechanical tests such as a uniaxial tensile test or a bending test.

It is distinct from the yield point, which is the onset of plastic deformation, and from the ultimate tensile strength, which is the maximum stress reached before necking begins. In ductile materials, fracture usually occurs after significant plastic deformation and necking; in brittle materials, fracture can occur with little or no plastic deformation and at much lower strains.

Measurement and interpretation: The fracture stress and the corresponding fracture strain (elongation) are reported from the test. Stress is measured in units such as megapascals (MPa), while strain is expressed as a percentage. Standardized procedures, such as those in tensile testing, define how specimens are prepared, loaded, and how fracture data are recorded. The fracture point can be influenced by temperature, strain rate, pre-existing flaws (cracks, inclusions), microstructure, and environmental conditions such as corrosion or hydrogen embrittlement.

Importance and applications: The töréspont is a key parameter in designing against catastrophic failure and in assessing material toughness. Designers use fracture mechanics concepts, including fracture toughness and critical flaw size, to predict failure in the presence of cracks. Understanding the fracture point helps compare materials for applications where brittleness, impact resistance, or high-strength requirements are critical.