Martensitischer

Martensitischer is an attributive adjective in German used to describe things related to martensite, a metastable phase in steels and some alloys. Martensite forms through a diffusionless transformation of austenite when the material is cooled rapidly or subjected to deformation. The transformation, known as martensitische Umwandlung, occurs as the temperature drops below Ms and progresses to Mf, changing the crystal structure from face-centered cubic austenite to body-centered tetragonal martensite. The process does not require long-range diffusion, allowing very fast transformation.

The resulting martensitic microstructure is typically hard and strong but brittle. Hardness and strength increase with carbon content and certain alloying elements, while ductility decreases. Tempering can reduce internal stresses and increase toughness, at the cost of some hardness. In steels, martensitic grades are common in stainless steel and tool steel families, including martensitic stainless steels such as 410 and 420, as well as various tool steels used for cutting, forming, and dies.

Beyond steels, martensitic transformations occur in other alloys and in shape memory materials such as nickel-titanium (Nitinol), where the martensitic phase is employed for actuators and smart materials. The term martensitischer is thus used to describe steel grades, heat-treatment concepts, or microstructural characteristics that involve martensite, for example martensitische Struktur, martensitischer Zustand, or martensitischer Anteil. In practice, the adjective adapts to gender and case of the noun, yielding forms like martensitischer Stahl or martensitische Struktur.