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
The corrosion performance of high pressure die-cast Al？6Si？3Ni （SN63） and Al-6Si-3Ni-2Cu （SNC632） alloys in 3.5%（mass fraction） NaCl solution was investigated. X-ray diffraction （XRD） and microstructural stu...The corrosion performance of high pressure die-cast Al？6Si？3Ni （SN63） and Al-6Si-3Ni-2Cu （SNC632） alloys in 3.5%（mass fraction） NaCl solution was investigated. X-ray diffraction （XRD） and microstructural studies revealed the presence of singlephase Si and binary Al3Ni/Al3Ni2 phases along the grain boundary. Besides, the single Cu phase was also identified at the grainboundaries of the SNC632 alloy. Electrochemical corrosion results revealed that, the SNC632 alloy exhibited nobler shift incorrosion potential （φcorr）, lower corrosion current density （Jcorr） and higher corrosion resistance compared to the SN63 alloy.Equivalent circuit curve fitting analysis of electrochemical impedance spectroscopy （EIS） results revealed the existence of twointerfaces between the electrolyte and substrate. The surface layer and charge transfer resistance （Rct） of the SNC632 alloy was higherthan that of the SN63 alloy. Immersion corrosion test results also confirmed the lower corrosion rate of the SNC632 alloy andsubstantiated the electrochemical corrosion results. Cu addition improved the corrosion resistance, which was mainly attributed to theabsence of secondary Cu containing intermetallic phases in the SNC632 alloy and Cu presented as single phase.展开更多
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.
基金financially supported by the World Class 300 R&D Program (S2404600)funded by the Small Business Administration of Korea through the Research Institute of Advanced Materials (041720170037)Magnesium Technology Innovation Center
文摘The corrosion performance of high pressure die-cast Al？6Si？3Ni （SN63） and Al-6Si-3Ni-2Cu （SNC632） alloys in 3.5%（mass fraction） NaCl solution was investigated. X-ray diffraction （XRD） and microstructural studies revealed the presence of singlephase Si and binary Al3Ni/Al3Ni2 phases along the grain boundary. Besides, the single Cu phase was also identified at the grainboundaries of the SNC632 alloy. Electrochemical corrosion results revealed that, the SNC632 alloy exhibited nobler shift incorrosion potential （φcorr）, lower corrosion current density （Jcorr） and higher corrosion resistance compared to the SN63 alloy.Equivalent circuit curve fitting analysis of electrochemical impedance spectroscopy （EIS） results revealed the existence of twointerfaces between the electrolyte and substrate. The surface layer and charge transfer resistance （Rct） of the SNC632 alloy was higherthan that of the SN63 alloy. Immersion corrosion test results also confirmed the lower corrosion rate of the SNC632 alloy andsubstantiated the electrochemical corrosion results. Cu addition improved the corrosion resistance, which was mainly attributed to theabsence of secondary Cu containing intermetallic phases in the SNC632 alloy and Cu presented as single phase.
