The improvement of grain refinement, texture modification and mechanical properties of pure Mg prepared by cyclic expansion extrusion with an asymmetric extrusion cavity

Abstract

In this article, a new type of severe plastic deformation process named cyclic expansion extrusion with an asymmetric extrusion cavity (CEE-AEC), was used to prepare pure magnesium with three passes repetitive deformation at 250 °C. This article mainly studies the microstructure evolution, texture analysis and mechanical properties of pure magnesium. The results display that the grain size is refined, from 74 um to 19 um, which is attributed to continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). With the increasing CEE-AEC passes, the texture is weakened, and the (0001) plane of a large number of grins are inclined from the ED direction. The Schmid factor that activates the basal slip system gradually increases from 0.29 to 0.3 after three passes. After three passes of CEE-AEC, from the tensile tests of the deformed samples at room temperature, it can be seen the samples have excellent comprehensive mechanical properties, the tensile yield strength (TYS) is 54 MPa, ultimate tensile strength (UTS) is 110 MPa, and fracture elongation is 19%.