Orowan Mechanism

Physical-Chemical Mechanism of Action

Dislocations in the metal matrix move around particles that cannot be fully cut. This movement leads to a hardening of the matrix and the formation of loops, which increase strength.

Metallurgical Relevance & Risks in Welding

With incoherent particles such as precipitates or hardening particles, the Orowan mechanism can lead to a significant increase in strength. However, this can also lead to increased stress concentration and cracking if dislocations are not properly managed.

Workshop Practice & Action Guidelines

To make effective use of the Orowan mechanism, aim for a homogeneous weld zone without strongly incoherent particles. Use suitable welding parameters such as temperature and voltage to control dislocations. In vaporization welding, it is especially important that precipitates are fully dissolved to avoid cracking.