Enhancement of mechanical and electrical properties in Al 6101 alloy by severe shear strain under hydrostatic pressure

Samples of commercially received aluminum AA6101 alloy are homogenized, quenched, and subjected to 2, 4, and 8 passes of Equal Channel Angular Pressing (ECAP) with 200 MPa of applied backpressure. Tensile strength of the alloy's samples increases with the accumulated strain to the double value of 400 MPa after 8 ECAP passes, while electrical conductivity slightly decreases from 51.3 to 48.2%IACS. Aging at 130 °C for 72 h is used to restore conductivity with very small loss of strength. Moreover, the increase in conductivity is directly proportional to the number of ECAP passes and conductivity exceeds those values measured for the as-received and solution treated states. Strong inhomogeneity of the microstructure and formation of a network of differently oriented shear bands during severe plastic deformation is observed, which is beneficial for simultaneous enhancement of mechanical and electrical properties.