Micro-Forming Using Ultrafine-Grained Aluminum Processed by Equal-Channel Angular Pressing

Avery high-purity (99.999%) aluminum was processed by equal-channel angular pressing (ECAP) at room temperature through 1 to 8 passes using a die with a channel angle of 90 degrees. Analysis shows that processing by ECAP produces an ultrafine-grained (UFG) structure with a grain size of approximate to 1.3 mu m and with microhardness and microstructural homogeneity. The mechanical properties and the fracture behavior were evaluated using micro-tensile testing after ECAP processing. A micro-forming process was used to fabricate a micro-turbine at ambient temperature and subsequent examination demonstrated that UFG pure aluminum gives higher strength and more uniform mechanical properties by comparison with conventional coarse-grained pure aluminum. The results confirm the very significant potential for using UFG pure aluminum for micro-forming at ambient temperature.