Equal channel angular pressing of steels (BCC), Al alloys (FCC) and pure titanium (HCP)

Abstract

Several aspects of equal channel angular pressing (ECAP) of steels, aluminum alloys and pure titanium were examined. They include grain refinement, microstructural modification, superplasticity, mechanical properties, etc. The grain refinement process of steels and aluminum alloys during ECAP appeared to be due to slip band formation, but that of titanium was entirely different. In addition, ECAP was found to be very effective in modifying microstructure. In the low carbon steels, for an example, a spheroidization of rod-like pearlitic cementite was enhanced and the spheroidized cementite particles were distributed uniformly in the ferrite matrix by ECAP and subsequent static annealing. The mechanical properties of the ECAPed FCC and BCC metals were measured and discussed in conjunction with the microstructural evolution during ECAP. In addition, the grain refinement mechanism in BCC and HCP metals by ECAP was analyzed on the basis of TEM observation of deformed microstructure.