Advances in theory: Martensite by design

The depth of scientific understanding of martensitic transformations provides a strong foundation for the predictive design of materials exploiting martensitic phenomena. Recent theoretical advances supporting this capability include two- and three-dimensional applications of Landau–Ginzburg theory to martensitic nucleation, and important refinements of multiscale kinetic theory. Accurate control of transformation kinetics in ferrous alloys has provided both (a) commercial stainless maraging steels exploiting isothermal martensitic transformation in processing and (b) designed secondary-hardening martensitic steels exploiting optimized dispersed-phase transformation toughening in service. Predictive design of low-misfit coherent nanodispersion-strengthened shape memory alloys offer significant advances in actuation power density and cyclic life.