Evolution of Quasicrystals and Long-Period Stacking Ordered Structures During Severe Plastic Deformation and Mixing of Dissimilar Mg Alloys Upon Friction Stir Welding
来源期刊：Acta Metallurgica Sinica2021年第1期
论文作者：Meichen Liang Hao Zhang Lifeng Zhang Peng Xue Dingrui Ni Weizhen Wang Zongyi Ma Hengqiang Ye Zhiqing Yang
文章页码：12 - 24
摘 要：Microstructural evolution during severe plastic deformation and mixing of Mg95.8Zn3.6Gd0.6 and Mg97Cu1Y2（at%） alloys upon friction stir welding was studied.A laminated onion-ring structure composed of alternative distribution of layers with significantly refined microstructures from diff erent alloys was formed in the stirred zone.Coarse quasicrystals were broken up and dispersed with most of them being transformed into cubic W-phase particles,and thick 18 R long-period stacking ordered plates were fractured and transformed into fine 14 H-LPSO lamellae in the stirred zone（SZ） experiencing complex material flow under high strain rate.Fine W-phase particles and 14 H-LPSO lamellae formed during dissimilar friction stir welding（FSW） usually have no specific orientation relationship with surrounding Mg matrix.Chemical measurements demonstrated occurrence of interdiff usion between dissimilar layers in the SZ.Phase transformation was observed for some particles of quasicrystals and long-period stacking ordered（LPSO） in regions slightly outside the SZ.An ultimate tensile strength of ～ 415 MPa and an elongation to failure of ～ 27.8%,both exceeding those of base materials,were obtained in the SZ,due to microstructural refinement and formation of a laminated structure.
Meichen Liang1，Hao Zhang1，Lifeng Zhang1，Peng Xue1，Dingrui Ni1，Weizhen Wang1，Zongyi Ma1，Hengqiang Ye1,2，Zhiqing Yang1
1. Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,School of Materials Science and Engineering,University of Science and Technology of China
摘 要：Microstructural evolution during severe plastic deformation and mixing of Mg95.8Zn3.6Gd0.6 and Mg97Cu1Y2（at%） alloys upon friction stir welding was studied.A laminated onion-ring structure composed of alternative distribution of layers with significantly refined microstructures from diff erent alloys was formed in the stirred zone.Coarse quasicrystals were broken up and dispersed with most of them being transformed into cubic W-phase particles,and thick 18 R long-period stacking ordered plates were fractured and transformed into fine 14 H-LPSO lamellae in the stirred zone（SZ） experiencing complex material flow under high strain rate.Fine W-phase particles and 14 H-LPSO lamellae formed during dissimilar friction stir welding（FSW） usually have no specific orientation relationship with surrounding Mg matrix.Chemical measurements demonstrated occurrence of interdiff usion between dissimilar layers in the SZ.Phase transformation was observed for some particles of quasicrystals and long-period stacking ordered（LPSO） in regions slightly outside the SZ.An ultimate tensile strength of ～ 415 MPa and an elongation to failure of ～ 27.8%,both exceeding those of base materials,were obtained in the SZ,due to microstructural refinement and formation of a laminated structure.
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