Development Microstructure and Mechanical Properties of Commercially Pure Titanium Processed by Equal Channel Angular Pressing and Cold Drawing

Equal channel angular pressing has been used to refine the grain size of commercially pure titanium (grade 2) as well as other metals and alloys. Titanium grade 2 is usually processed at about 350 °C because it lacks sufficient ductility at lower temperatures. The warm processing temperature limits the capability of the equal channel angular pressing technique in improving the strength of titanium grade 2. We have employed cold drawing following warm equal channel angular pressing to further refine the grains and improve the strength of titanium grade 2. Ti billets were first processed for eight passes via route BC, with a clockwise rotation of 90° between adjacent passes. They were further processed by successive cold drawing to an accumulative reduction in cross-section area by 50 %. This paper reports the surface quality, microstructures and mechanical properties of these titanium billets processed by a combination of equal channel angular pressing and drawing.