Dispersionhärdning

Dispersionhärdning, also known as dispersion strengthening or precipitation hardening in English, is a strengthening mechanism used in materials science, particularly in metallurgy. It involves the introduction of finely dispersed, insoluble particles within a metallic matrix. These particles act as obstacles to the movement of dislocations, which are line defects in the crystal lattice responsible for plastic deformation. By impeding dislocation motion, dispersion hardening increases the yield strength and hardness of the material.

The process typically begins with a supersaturated solid solution, often achieved through alloying and subsequent heat treatment. This is followed by a controlled aging process, which causes the precipitation of small, coherent or semi-coherent particles from the matrix. The size, distribution, and coherency of these precipitate particles are critical factors determining the effectiveness of the strengthening. Larger or more numerous particles generally lead to greater strengthening, up to a certain optimum.

Common examples of materials strengthened by this mechanism include aluminum alloys, superalloys, and some stainless steels. The specific precipitates and matrix materials vary widely depending on the alloy system and desired properties. Dispersion hardening is a crucial technique for achieving high-strength materials that can withstand demanding applications, such as in the aerospace and automotive industries. The effectiveness of dispersion hardening is often assessed by the increase in yield strength and hardness compared to the unstrengthened material.