Jernmynn

Jernmynn is a fictional metallic alloy described in speculative fiction and worldbuilding contexts. In the imagined settings where it appears, jernmynn is prized for a combination of high tensile strength, excellent fatigue resistance, and good surface hardness, along with relatively low density for an iron-based alloy. It is often portrayed as a near-ideal material for structural components, armor plating and high-performance machinery.

The alloy is depicted as iron-rich, with small but crucial additions of chromium, vanadium and a trace amount of a rare earth element. Its microstructure is said to form fine martensite with carbide networks that harden during heat treatment. Jernmynn is described as having a high yield strength and good toughness, maintaining performance over wide temperature ranges and showing excellent wear resistance. It is usually magnetic at room temperature, though heat treatments can modify its magnetic behavior.

Manufacture involves specialized smelting in inert or vacuum environments, followed by precise alloying and controlled quenching and tempering. The process is said to impart a fine-grained structure that resists crack propagation and provides stable mechanical properties under cyclic loading.

In usage, jernmynn appears in starships, armored exosuits, turbines and turbine blades, as well as in heavy frame constructions. It is often presented as scarce and expensive due to the difficulty of extracting and processing its alloying elements, but valued for longevity and performance.

Origin and naming: the term is sometimes linked to a folkloric tradition where 'jern' denotes iron, and 'mynn' implies strength. See also iron-based alloys.