Mechanical properties and corrosion behaviour of ultrafine-grained AA6082 produced by equal-channel angular pressing

The mechanical properties and corrosion behaviour of AA6082 with ultrafine-grained (UFG) microstructure were investigated. The material was processed by equal-channel angular pressing (ECAP) up to eight extrusions at room temperature in a 90°-die with active backpressure. Besides the peak-aged temper, which provides maximum strengths and strongly reduced ductility, the solution heat treated condition was considered as well. Combined with post-ECAP aging, an optimum of high strength, ductility and impact toughness was achieved. The corrosion investigations and the examination of the corrosion damage of the UFG-materials show higher pitting corrosion resistance compared to the unprocessed material. The optimised condition was used for the production of screw prototypes which showed appreciable higher strength and ductility compared to the identically manufactured screws from the CG counterpart. Such materials are potential candidates to be used for several engineering applications such as high strength screws even at higher temperatures.