Low temperature compaction of titanium alloy powder by equal channel angular extrusion with back pressure

It is shown that the use of Equal Channel Angular Extrusion (ECAE) with applied back pressure for compaction of powder allows significantly decrease the temperatures of consolidation compare to those used in conventional practice. The possibility to lower the processing temperature would give a cost-effective method to produce a cheaper product as well as minimise the contamination of powder and compact with gaseous constituents known to be harmful to resultant properties. The novelty of the approach arises from the notion that severe shear deformation triggers several physical mechanisms contributing to improved compaction. The compacts produced from CP-Ti at temperatures in the range from room temperature to 300°C by ECAE with back pressure have a relative density above 99.5%. Efficient consolidation of pre-alloyed (PA) Ti-6A1-4V (HDH) powder at temperatures of 400°C and below, achieving relative densities of 98.3-98.6% and green strengths up to 750 MPa has been performed.