In this study,Mg-9 Al-1 Si-1 SiC(wt%)composites were processed by multi-pass equal-channel angular pressing(ECAP)at various temperatures,and their microstructure evolution and strengthening mechanism were explored.Res...In this study,Mg-9 Al-1 Si-1 SiC(wt%)composites were processed by multi-pass equal-channel angular pressing(ECAP)at various temperatures,and their microstructure evolution and strengthening mechanism were explored.Results showed that the as-cast microstructure was composed of anα-Mg matrix,discontinuous Mg17Al12 phase,and Chinese script-shaped Mg2Si phase.After solution treatment,almost all of the Mg17Al12 phases were dissolved into the matrix,whereas the Mg2Si phases were not.The subsequent multi-pass ECAP at different temperatures promoted the dynamic recrystallization and uniform distribution of the Mg17Al12 precipitates when compared with the multipass ECAP at a constant temperature.A large number of precipitates can effectively improve the nucleation ratio of recrystallization through a particle-stimulated nucleation mechanism.In addition,the SiC nanoparticles were mainly distributed at grain boundaries,which effectively prevented dislocation movement.The excellent comprehensive mechanical properties can be attributed to grain boundary strengthening and Orowan strengthening.展开更多
The effect of Nd addition on the microstructure and mechanical properties of as-extruded Mg-9Gd-0.5Zr(wt.%) alloy was investigated. The Mg-9Gd-0.5Zr and Mg-9Gd-2Nd-0.5Zr alloys were extruded at 673 K. The elongated no...The effect of Nd addition on the microstructure and mechanical properties of as-extruded Mg-9Gd-0.5Zr(wt.%) alloy was investigated. The Mg-9Gd-0.5Zr and Mg-9Gd-2Nd-0.5Zr alloys were extruded at 673 K. The elongated non-dynamic recrystallized(un-DRXed) grains disappear after adding Nd, and uniformly distributed dynamic recrystallized grains with a grain size of 1.68 μm were obtained in the alloy. In addition, numerous nano-Mg5(Gd,Nd)particles were found to precipitate dynamically in the Mg-9Gd-2Nd-0.5Zr alloy, which gave rise to the dynamic recrystallization process via providing nucleation energy through hindering the release of deformation energy and promoting an increase in the strength through the Orowan strengthening mechanism. Moreover, the dynamically recrystallized(DRXed) grains have a weak texture, which plays a significant role in improving the ductility. Therefore,the Nd addition favors the improvement of strength and elongation for the as-extruded Mg-9Gd-0.5Zr alloy,simultaneously.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51404166,51704209,and U1810208)Shanxi province scientific facilities and instruments shared service platform of magnesium-based materials electric impulse aided forming(No.201805D141005)+4 种基金Science and Technology Major Project of Shanxi province(Nos.20191102008,20191102007,20191102004,and 20181101008)Natural Science Foundation of Shanxi Province(No.201701D121045)Shanxi Province Science Foundation for Youths(No.2016021063)The Projects of International Cooperation in Shanxi(No.201803D 421086)。
文摘In this study,Mg-9 Al-1 Si-1 SiC(wt%)composites were processed by multi-pass equal-channel angular pressing(ECAP)at various temperatures,and their microstructure evolution and strengthening mechanism were explored.Results showed that the as-cast microstructure was composed of anα-Mg matrix,discontinuous Mg17Al12 phase,and Chinese script-shaped Mg2Si phase.After solution treatment,almost all of the Mg17Al12 phases were dissolved into the matrix,whereas the Mg2Si phases were not.The subsequent multi-pass ECAP at different temperatures promoted the dynamic recrystallization and uniform distribution of the Mg17Al12 precipitates when compared with the multipass ECAP at a constant temperature.A large number of precipitates can effectively improve the nucleation ratio of recrystallization through a particle-stimulated nucleation mechanism.In addition,the SiC nanoparticles were mainly distributed at grain boundaries,which effectively prevented dislocation movement.The excellent comprehensive mechanical properties can be attributed to grain boundary strengthening and Orowan strengthening.
基金supported by the Natural Science Foundation of Shanxi Province, China (Nos. 20210302123135, 20210302123163, 201901D211096, 201901D111272)Youth Program of National Natural Science Foundation of China (No. 51901153)+1 种基金Science and Technology Major Project of Shanxi Province, China (Nos. 20191102008, 20191102007, 20191102004)Shanxi Province Scientific Facilities and Instruments Shared Service Platform of Magnesium-based Materials Electric Impulse Aided Forming, China (No. 201805D141005)。
文摘The effect of Nd addition on the microstructure and mechanical properties of as-extruded Mg-9Gd-0.5Zr(wt.%) alloy was investigated. The Mg-9Gd-0.5Zr and Mg-9Gd-2Nd-0.5Zr alloys were extruded at 673 K. The elongated non-dynamic recrystallized(un-DRXed) grains disappear after adding Nd, and uniformly distributed dynamic recrystallized grains with a grain size of 1.68 μm were obtained in the alloy. In addition, numerous nano-Mg5(Gd,Nd)particles were found to precipitate dynamically in the Mg-9Gd-2Nd-0.5Zr alloy, which gave rise to the dynamic recrystallization process via providing nucleation energy through hindering the release of deformation energy and promoting an increase in the strength through the Orowan strengthening mechanism. Moreover, the dynamically recrystallized(DRXed) grains have a weak texture, which plays a significant role in improving the ductility. Therefore,the Nd addition favors the improvement of strength and elongation for the as-extruded Mg-9Gd-0.5Zr alloy,simultaneously.
