Tube equal channel angular extrusion (tECAE) of Mg–3Al–1Zn alloy

Highlights: • Tube ECAE processing successfully produced fine grained Mg-3Al-1Zn tubes. • Tube ECAE SPD processed AZ31 directly at 120 °C. • Improvement in mechanical properties and texture modification are obtained via tECAE. • VPSC modeling predicted texture and deformation mode activities. This study describes a severe plastic deformation processing technique for tubular materials, in the interest of enhancing mechanical properties via grain refinement and crystallographic texture control. The process, dubbed as tube equal channel angular extrusion (tECAE), is used to process the Mg–3Al–1Zn (AZ31) magnesium alloy at low temperatures. Mg alloys often suffer from low strength levels derived from coarse grain size, strong crystallographic texture, and mechanical anisotropy; hence, AZ31 acts as an ideal candidate for tECAE, as AZ31 and other Mg alloys tubes have excellent potential application in various industries. Here, the texture evolution of one pass of tECAE processing at 200 °C, 175 °C, and 120 °C was assessed, where tECAE produced drastically refined grains and increased strength levels after only one pass. The texture evolution and the active deformation modes, and their relative activities, were successfully predicted using a viscoplastic self-consistent (VPSC) crystal plasticity model as a function of processing temperature, for the first time for the tECAE process. Overall, tECAE is shown to be a useful technique for quickly obtaining improved mechanical properties in Mg alloy tubes, and it can be applied to other materials in tubular form as well.