Effect of equal channel angular pressing on strain deformation behavior of ultrafine grained during low temperature superplasticity of AA5083

Abstract

AA5083 with ultrafine grain structure was produced through equal channel angular pressing using different levels of ECAP tensions, underwent a series of tensile tests. The superplasticity temperature 573 K at low temperatures. This study investigate how varying the ECAP strain influences the distinctive microstructure of the alloy and its impact on deformation mechanisms within the low-temperature superplasticity range. A fraction of the high angle borders increased when the equal channel angular pressing strain was increased from 1 to 2, while the sub-grain size stayed nearly same. This was the most applicable microstructural evolution. After double passes, the material showed superplastic elongations, but after single pass, it did not show low temperature superplasticity. Upon analyzing the mechanical data using typical deformation mechanisms, it was determined that dislocation climb controlled the samples deformation after the first pass, whereas grain boundary sliding was responsible for the sample's low temperature superplasticity after the second pass. In the present study, we explored the differences in deformation mechanisms by considering the microstructures formed under various ECAP strains. Equal channel angular pressing with a BC route and an effective strain of 1∼2, we created an ultrafine-grained AA5083. A significant increase was seen in the fraction of particles measuring 1.8–3.8 μm under the current ECAP conditions. The implementation of equal channel angular pressing, there was a significant increase in the occurrence of voids with sizes ranging from 0.8 to 1.8 μm. According to the current analysis and results, if moderate superplastic elongation is guaranteed, it may be preferable to have fewer equal channel angular pressing passes than those that result in the largest elongation while taking into account cavitation damage and the low temperature superplasticity of ultrafine grained AA5083 used in commercial applications.