Using severe plastic deformation for the processing of structural metals

The grain sizes of structural metals may be substantially refined, typically to the submicrometer to nanometer range, by imposing severe plastic deformation in processes such as High-Pressure Torsion (HPT) and Equal-Channel Angular Pressing (ECAP). This paper describes the principle of ECAP and illustrates the application of this procedure to representative materials. Several factor influence the microstructures attained in ECAP including (i) the processing route incorporating the rotation of samples between consecutive pressings, (ii) the channel angle contained with the ECAI die, (iii) the speed of pressing and (iv) the temperature at which the pressing is conducted. These various factors are discussed and illustrated with experimental examples.