On improving the formability of AA6061/SiCp composite synthesized using friction stir processing

Friction stir process is a potentially useful method for producing composites of enhanced surface properties. In this work, an AA6061/SiCp composite, synthesized using friction stir processing, was tested in three-point bending and uniaxial hot tensile and bi-axial stressing to assess its formability. Bending test results reveal an increased bending strength in the composite compared with the AA6061 alloy, subjected to friction stir processing, but without the addition of the silicon carbide particles. Based on the hot tensile tests, the biaxial stressing temperatures were fixed as 623 K and 673 K. Bi-axial stressing reveals that a maximum bulge height of 18 mm could be obtained by forming into a cavity of 59 mm diameter at a pressure of 0.2 MPa. Based on the results, process parameters such as formed bulge height, forming time, strain rate and strain rate sensitivity index were determined. In the present experiments, the strain rate sensitivity index increased with increasing forming pressure and reached a maximum value of 0.40 at a forming pressure of 0.25, as the latter variable was increased from 0.20 MPa to 0.25 MPa. The present findings can pave the way for the commercial exploitation of friction stir process-technology-based, efficient processing of the AA6061/SiCp composite.