Martensite in Steels

The name martensite is after the German scientist Martens. It was used originally to describe the hard microconstituent found in quenched steels. Martensite remains of the greatest technological importance in steels where it can confer an outstanding combination of strength (> 3500MPa) and toughness (> 200MPam 1 2 ). Many materials other than steel are now known to exhibit the same type of solid-state phase transformation, known as a martensitic transformation, frequently also called a shear or displacive transformation. Martensite occurs in, for example, nonferrous alloys, pure metals, ceramics, minerals, inorganic compounds, solidified gases and polymers (Table 1). We shall review first the experimental facts about martensite and then proceed to explain them.