Production of fine-grained aluminum alloy by friction stir processing

Friction stir processing (FSP) was applied to 1050 aluminum alloy (commercially pure aluminum) to produce fine-grained structure. By varying the processing condition, the temperature at the FSP zone could be controlled from 393K to 733K. When the temperature at the FSP zone was below 473K, fine-grained 1050 aluminum alloy could be produced. For example, the grain size in the FSP zone is 0.5-1mum and 4-8mum for the rolled sample and the annealed sample, respectively. That is, grain size in the FSP zone depended on the condition of the base metal, e.g. the rolled sample and the annealed sample. These results show that FSP can be a useful processing to produce fine-grained aluminum alloy.