Substitutional Solid Solution Hardening
Substitutional solid solution strengthening increases strength by inserting alloying elements of similar size into regular lattice sites, creating elastic strain and making the metal harder.
Physical-Chemical Mechanism of Action
Substitutional solid solution hardening occurs by inserting alloying elements of similar atomic size at regular positions in the metal lattice. These elements replace atoms of the base metal and distort the lattice, creating elastic stresses.
Metallurgical Relevance & Welding Risks
This hardening increases strength and toughness, but can also lead to increased hardness. With too high alloy content, the material can become glass-hard and crack. Additionally, substitution can lead to deformation weakening if stresses are too high.
Workshop Practice & Action Guidelines
To effectively maintain substitutional solid solution hardening, it is important to assign an appropriate content of alloying elements and design the welding procedure so that stresses in the metal lattice do not become too high. This can be achieved by careful material selection and controlled cooling. Recommended alloying elements are e.g. Ni (nickel), Cr (chromium), or Mo (molybdenum).