A microstructural study of a melt-spun ultra high-strength alloy steel

Melt spinning in a controlled atmosphere has been used to produce ribbons of an ultra high-strength alloy steel. The microstructure of these ribbons has been investigated using both optical and transmission electron microscopy. Comparison of the microstructure with that produced by conventional solid-state quenching shows that the martensitic structure is refined in the melt-spun ribbon and the formation of alloy carbides suppressed. These factors lead to a considerable increase in hardness of the meltspun ribbon with respect to that of the solid-state quenched material. The occurrence of interlath austenite is discussed in terms of the crystallography of the martensite transformation.