Micro extrusion of ultrafine grained titanium prepared by ECAP
Micro compression and micro extrusion experiments of ultrafine grained titanium cylindrical specimens in diameters of 4, 2, and 1 mm prepared by equal channel angular pressing (ECAP) were conducted on the micro plastic forming test machine. The effects of specimen size, grain size, deformation temperature and extrusion speed on the flow stress and forming properties of the ultrafine grained pure titanium were investigated. The flow stress of ultrafine grained pure titanium specimen decreases with decreasing specimen size. The yield limit of pure titanium with refined grain prepared by ECAP is significantly greater than that of coarse grained specimen. Also the research results show that the flow stress of specimen increases with decreasing deformation temperature and with the increase of the strain rate, and the ultrafine grained pure titanium possesses good micro forming properties at deformation temperature of 300 °C.