Fatigue behavior of Al-Cu alloy subjected to different numbers of ECAP passes

Strain-controlled fatigue tests on Al-Cu alloy subjected to different number of ECAP (Equal channel angular pressing) passes were performed describing the fatigue properties and damage mechanism. Cast Al and Cu ingots were used and ECAP at room temperature using a solid die and was subjected to repetitive pressing were rotated by 90 degree in the same direction between each pass. The specimens were mechanically polished followed by electropolishing in a solution of HClO4 and C2H5OH. The results and observations indicate that the microstructure of the As-cast alloy consists of Al solution and few of dot like phases distributed in the matrix, as the Ultimate tensile strength (UTS) of the As-cast alloy was 83.2 MPa, while after four passes the UTS increases to 216.2 MPa. Strain-controlled fatigue tests of Al-Cu alloy subjected to different number of ECAP passes displayed cyclic softening and on multipass ECAP treatment it decreased the shape parameter of hysteresis loop of the Al-Cu alloy.