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A novel severe plastic deformation method and its effect on microstructure, texture and mechanical properties of Mg-Gd-Y-Zn-Zr alloy.
- Source :
-
Journal of Alloys & Compounds . May2020, Vol. 822, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
-
Abstract
- In this paper, cyclic expansion extrusion with an asymmetrical extrusion cavity (CEE-AEC) was proposed as a novel severe plastic deformation process for fabricating bulk ultrafine-grained (UFG) metals. Increasing the size of the processed sample and introducing the shear strain by attaching an asymmetrical extrusion cavity are the core advantages of this technology. The CEE-AEC process was applied to Mg-13Gd-4Y–2Zn-0.4Zr alloys for four passes deformation with the decreasing temperature, and then the microstructure evolution, texture analysis, and mechanical properties were investigated. Microstructure results show that a dramatical grain refinement is achieved from initial value of 24 ± 0.3 μm to 1.4 ± 0.3 μm which is mainly led by continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) as well as the particle-stimulated nucleation (PSN) induced by interdendritic long-period stacking ordered (LPSO) phases. With increasing CEE-AEC passes, the intensities of basal texture are gradually weakened, and the basal plane tends to incline to transverse and normal directions with different degrees of different passes, leading to a remarkable increase in Schmid factor for the activation of basal slip system. Tensile tests at room temperature (RT) indicate that the samples after three-passes of CEE-AEC exhibit the best comprehensive mechanical properties with tensile yield strength (TYS) of 302 MPa, ultimate tensile strength (UTS) of 330 MPa, and fracture elongation of 6.1%, which are mainly ascribed to the grain refinement, broken of interdendritic block-shaped LPSO phases, and texture modification. • A novel SPD method entitled CEE-AEC was proposed. • The Mg-13Gd-4Y–2Zn-0.4Zr alloy was processed by CEE-AEC with consecutive four passes deformation. • A significant grain refinement from initial 24 ± 0.3 μm to 1.4 ± 0.3 μm was obtained. • Continuous and discontinuous dynamic recrystallizations took place during CEE-AEC. • The mechanical properties were contributed from the competitive of fine grains strengthening and texture modification. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09258388
- Volume :
- 822
- Database :
- Academic Search Index
- Journal :
- Journal of Alloys & Compounds
- Publication Type :
- Academic Journal
- Accession number :
- 141638960
- Full Text :
- https://doi.org/10.1016/j.jallcom.2020.153698