Mechanical properties and pitting corrosion behavior of Al5085 alloy processed via ECAP

In this paper, the impact of the number of passes of equal channel angular pressing (ECAP) on mechanical properties and corrosion behavior of Al5085 alloys in an HNO3 solution is investigated. After a single pass of ECAP, the ultimate tensile strength (UTS) was increased noticeably from 275 MPa to 342 MPa. Also, the yield strength (YS) and microhardness were improved from ~82 MPa to ~118.5 MPa and 94 HV to 136 HV, respectively. After the second pass all UTS, YS, and microhardness increased by ~13.5%, ~17.8%, and ~11.7% compared to the first pass. Meanwhile, the elongation to failure was reduced by ~15% and ~7.5% after one and two passes of the ECAP, respectively. According to scanning electron microscope (SEM) micrographs, unlike the unprocessed sample in which there is no evidence of pitting corrosion occurrence, after one pass ECAP, the pitting corrosion occurred through all the surfaces of the sample. Also, there is no evidence of pitting corrosion after two passes of ECAP.