Recent Progress on SPD Processes Empowered by Hydrostatic Pressure

Processing ultrafine-grained (UFG) and nanostructured (NS) materials in industrial size with simultaneous strength and ductility are the main challenges in severe plastic deformation (SPD) approaches. Hydrostatic SPD methods are a modified version of conventional SPD and forming methods with the difference of conducting fluid between the die and the sample to reduce surface contact or metal-to-metal contact. Recent studies show that hydrostatic SPD methods could process relatively long samples, making them usable in industrial applications. Also, a good combination of high strength and low ductility loss and more homogeneous properties could be achieved due to higher hydrostatic pressure. This article reviews hydrostatic SPD methods, their unique properties, and their capabilities.