Mechanical properties at room temperature of an Al-Zn-Mg-Cu alloy processed by equal channel angular pressing

摘要

Tensile tests were conducted to evaluate the influence of equal-channel angular\udpressing (ECAP) on the mechanical properties at room temperature of overaged Al\ud7075-O alloy. ECAP processing was performed using route BC at different temperatures\udand number of passes, i.e. different processing severity conditions. The maximum load\ud(Fmax) recorded during the last pass of each ECAP path considered in this study is a very\udgood estimation of the processing severity. The mechanical properties were studied in\udterms of the balance between tensile strength and ductility. In the processed Al 7075-O\udalloy, the grain size was reduced down to ∼150 nm. Consequently, tensile testing at\udroom temperature revealed a significant increase in the maximum tensile strength after\udECAP with respect to the as start material. In the present study, as the processing\udseverity increases with the number of ECAP passes or with the decrease in processing\udtemperature, there is a consistent trend of increment in ultimate tensile strength with\udminor decrease in uniform plastic elongation respect to the first ECAP pass at room\udtemperature. This is in contrast to the behaviour after more severe plastic deformation\udconditions, where an increase in strength together with a strong decrease in elongation\udwould be expected.