Festigkeits

Festigkeit is a term used in materials science and engineering to describe the inherent ability of a material to withstand mechanical loads without failure. In practice it covers several related properties, commonly referred to as strength properties: tensile strength, yield strength, compressive strength, and shear strength. Tensile strength is the maximum stress a material can sustain in tension before necking or fracture; yield strength is the stress at which plastic deformation begins under load. Ultimate tensile strength is another term used for the maximum stress reached in a tensile test. Notch toughness and impact strength describe behaviour under sudden or concentrated loads.

Strength values are determined by standardized testing, such as tensile tests following ISO 6892 or DIN EN standards, which yield numbers like yield strength, ultimate tensile strength, and elongation at break. Units are typically megapascals (MPa) or gigapascals (GPa). Material factors such as chemical composition, microstructure, grain size, and heat treatment strongly influence Festigkeit; processes like tempering, annealing, work hardening, and operating temperature can raise or lower it. There is often a trade-off between strength and ductility, and very high strength may reduce toughness.

In engineering practice, Festigkeit informs material selection and design safety factors. Designers seek a balance between high strength and adequate ductility to avoid brittle failure. The concept applies across metals, polymers, ceramics, and composites, each with characteristic strength regimes and failure modes.