Optimized Combination of Strength and Electrical Conductivity of Al-Mg-Si Alloy Processed by ECAP with Two-Step Temperature

The mechanical properties and electrical conductivity of 6063 aluminum alloy subjected to equal-channel angular press (ECAP) at room temperature (RT), 200 °C, and two-step temperature schedule (TST) have been investigated in this study. The TST refers to one pass at 200 °C followed by further successive pressing at RT. It is shown that this method is effective in obtaining the combination of high strength and electrical conductivity. After two passes, the higher strength can be achieved in TST condition (328 MPa yield strength and 331 MPa ultimate tensile strength), where the changing parameter is processing temperature from the first pass at 200 °C to the second pass at RT, as compared to two passes in RT condition (241 MPa yield strength and 250 MPa ultimate tensile strength) and two passes in 200 °C condition (239 MPa yield strength and 258 MPa ultimate tensile strength). This performance could be associated with grain refinement and nanosized precipitates in TST condition. Moreover, in contrast to RT condition, a higher electrical conductivity was observed in TST condition. It reveals that high strength and electrical conductivity of 6063 aluminum alloy can be obtained simultaneously by ECAP processing in TST condition because of ultrafine-grained microstructure and nanosized precipitates.