Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-r...Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-ray diffraction （XRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.展开更多
Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD)...Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD) and electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA). Two types of phase equilibrium were identified at the different temperatures. One is two-phase equilibrium contained the Mg solid solution and T-phase. The other is three-phase equilibrium which contained the Mg solid solution, MgZn phase and T-phase. T-phase was stable as the temperature changed. The La content in T-phase is constant which is about 8±0.3% (atom fraction); but the Mg content and Zn content of that is changed, and the Zn content in T-phase was from 16.1% to 44%. The solubility of La in MgZn phase was increased from 1.2% to 1.6% as the temperature increasing from 200 to 350 ℃.展开更多
The phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350°C have been investigated by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. It has been shown that the l...The phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350°C have been investigated by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. It has been shown that the linear compound (Mg,Zn)17La2 existed in the Mg-Zn-La system at 350°C. The linear compound (so-called T phase) was with the C-centred orthorhombic crystal structure induced by the solution of significant quantities of the third element. The three-phase region α(Mg) + MgZn(La) + T and the two-phase region composed of the α(Mg) and the linear-compound T phase existed in the Mg-rich corner of the Mg-Zn-La system at 350°C.展开更多
Alloys with different compositions in Mg-rich corner of Mg-Zn-La system at 400 ℃ were prepared,the phase equilibrium in the Mg-rich corner of Mg-Zn-La system was determined by scanning electron microscopy(SEM),electr...Alloys with different compositions in Mg-rich corner of Mg-Zn-La system at 400 ℃ were prepared,the phase equilibrium in the Mg-rich corner of Mg-Zn-La system was determined by scanning electron microscopy(SEM),electron probe microanalysis based on energy dispersive X-ray spectroscopy(EPMA-EDS) and X-ray diffraction(XRD),and the isothermal section at 400 ℃ was established. The results show that there exists a ternary compound(T-phase) with a constant La content and changable Mg/Zn contents in the Mg-Zn-La system. The mole fraction of La in T-phase is about 8%,and that of Zn is from 16% to 43%. There exist a two-phase equilibrium which consists of T-phase plus hcp-Mg and a three-phase equilibrium which is composed of T-phase,hcp-Mg and a liquid phase(L-phase) at 400 ℃ . The L-phase consists of 70% Mg,30% Zn and is free of La.展开更多
以实验室自制的无机纳米粒子镁铝锌镧碳酸根型层状双羟基氧化物(Mg Al Zn La-CO3LDHs)为协效剂,以聚磷酸铵(APP)和三聚氰胺(MA)为复配膨胀阻燃剂(IFR),与聚丁二酸丁二醇酯(PBS)熔融共混制备了PBS膨胀阻燃体系;利用锥形量热仪在25 k W/m...以实验室自制的无机纳米粒子镁铝锌镧碳酸根型层状双羟基氧化物(Mg Al Zn La-CO3LDHs)为协效剂,以聚磷酸铵(APP)和三聚氰胺(MA)为复配膨胀阻燃剂(IFR),与聚丁二酸丁二醇酯(PBS)熔融共混制备了PBS膨胀阻燃体系;利用锥形量热仪在25 k W/m2的热辐射条件下,研究了Mg Al Zn La-CO3LDHs对PBS膨胀阻燃体系动态燃烧行为的影响。结果表明,Mg Al Zn La-CO3LDHs的加入不仅明显降低了PBS膨胀阻燃体系的热释放速率(HRR)、烟生成速率(SPR)、质量损失速率(MLR),而且CO的释放量也得到了很好的控制,提高了体系的火灾性能指数(FPI)。Mg Al Zn La-CO3LDHs明显抑制了PBS膨胀阻燃体系的动态燃烧行为,同时表现出与膨胀阻燃剂良好的协效作用。展开更多
Basic thermal properties and mechanical properties are critical parameters for the structural magnesium alloys.Solute atoms and second phases can improve mechanical properties,but are deteriorating the heat dissipatio...Basic thermal properties and mechanical properties are critical parameters for the structural magnesium alloys.Solute atoms and second phases can improve mechanical properties,but are deteriorating the heat dissipation performance.Through experimental determination of alloys,it is found that REMg12 phases have fewer negative impacts on thermal diffusivities thanτ;phases.With the same intermetallic compound,the solute atom Zn have more negative influences on thermal diffusivities of Mg-Zn-La/Ce alloys than the content of second phases.In order to quantitatively evaluate thermal conductivities and further design Mg alloys with both high strength and high thermal conductivity,a calculated method is provided to describe the thermal diffusivity of alloys as a function of alloy composition and phase constitution.A set of parameters for expression of thermal diffusivity of Mg-Zn-La/Ce alloys were obtained through assessing the experimental data.The thermal conductivities of Mg-Zn-La/Ce system were predicted and agreed well with experimental values with calculation error of 1.6%and standard error of±3.0 W/(m K).The calculation method considering thermal diffusivity resistivity improves the calculation accuracy and would be physically significant.展开更多
The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the a...The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the as-cast alloy and restrain grain growth during solution treatment, which was derived from the constitutional supercooling during solidification process and the formation of stable intermetallic compounds Ce Mg12 and Mg17La2. Furthermore, Ce/La microalloying and solution treatment resulted in an evolution from the original lamellar Ca2Mg6Zn3/α-Mg to the divorced eutectic structure. The thermal stability of Mg-Zn-Ca alloy could be effectively improved by Ce/La addition, because the low-melting-point binary Mg-Zn phase was transformed to Mg x Zn y-Ca-（Ce/La） phase with higher thermal stability and the amount of Ca2Mg6Zn3/α-Mg eutectic structure was reduced.展开更多
基金National Natural Science Foundation of China(No.50471025)Natural Science Foundation of Liaoning Province (No.20052028).
文摘Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-ray diffraction （XRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.
基金the National Natural Science Foundation of China (50471025)Natural Science Foundation of Lia-oning Province (20052028)National Key Technology R &D Program(2006BAE04B09-7)
文摘Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD) and electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA). Two types of phase equilibrium were identified at the different temperatures. One is two-phase equilibrium contained the Mg solid solution and T-phase. The other is three-phase equilibrium which contained the Mg solid solution, MgZn phase and T-phase. T-phase was stable as the temperature changed. The La content in T-phase is constant which is about 8±0.3% (atom fraction); but the Mg content and Zn content of that is changed, and the Zn content in T-phase was from 16.1% to 44%. The solubility of La in MgZn phase was increased from 1.2% to 1.6% as the temperature increasing from 200 to 350 ℃.
基金This work is financially supported by the National Natural Science Foundation of China (No. 50471025)
文摘The phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350°C have been investigated by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. It has been shown that the linear compound (Mg,Zn)17La2 existed in the Mg-Zn-La system at 350°C. The linear compound (so-called T phase) was with the C-centred orthorhombic crystal structure induced by the solution of significant quantities of the third element. The three-phase region α(Mg) + MgZn(La) + T and the two-phase region composed of the α(Mg) and the linear-compound T phase existed in the Mg-rich corner of the Mg-Zn-La system at 350°C.
基金Project(50471025) supported by the National Natural Science Foundation of ChinaProject(20052028) supported by the Natural Science Foundation of Liaoning Province, China
文摘Alloys with different compositions in Mg-rich corner of Mg-Zn-La system at 400 ℃ were prepared,the phase equilibrium in the Mg-rich corner of Mg-Zn-La system was determined by scanning electron microscopy(SEM),electron probe microanalysis based on energy dispersive X-ray spectroscopy(EPMA-EDS) and X-ray diffraction(XRD),and the isothermal section at 400 ℃ was established. The results show that there exists a ternary compound(T-phase) with a constant La content and changable Mg/Zn contents in the Mg-Zn-La system. The mole fraction of La in T-phase is about 8%,and that of Zn is from 16% to 43%. There exist a two-phase equilibrium which consists of T-phase plus hcp-Mg and a three-phase equilibrium which is composed of T-phase,hcp-Mg and a liquid phase(L-phase) at 400 ℃ . The L-phase consists of 70% Mg,30% Zn and is free of La.
文摘以实验室自制的无机纳米粒子镁铝锌镧碳酸根型层状双羟基氧化物(Mg Al Zn La-CO3LDHs)为协效剂,以聚磷酸铵(APP)和三聚氰胺(MA)为复配膨胀阻燃剂(IFR),与聚丁二酸丁二醇酯(PBS)熔融共混制备了PBS膨胀阻燃体系;利用锥形量热仪在25 k W/m2的热辐射条件下,研究了Mg Al Zn La-CO3LDHs对PBS膨胀阻燃体系动态燃烧行为的影响。结果表明,Mg Al Zn La-CO3LDHs的加入不仅明显降低了PBS膨胀阻燃体系的热释放速率(HRR)、烟生成速率(SPR)、质量损失速率(MLR),而且CO的释放量也得到了很好的控制,提高了体系的火灾性能指数(FPI)。Mg Al Zn La-CO3LDHs明显抑制了PBS膨胀阻燃体系的动态燃烧行为,同时表现出与膨胀阻燃剂良好的协效作用。
基金financially supported by the National Natural Science Foundation of China(Nos.51871143 and 51671118)Science and Technology Committee of Shanghai(No.19010500400)+1 种基金the“Chenguang”project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(17CG42)Shanghai Engineering Research Center of Metal Parts Green Remanufacture(No.19DZ2252900)from Shanghai Engineering Research Center Construction Project。
文摘Basic thermal properties and mechanical properties are critical parameters for the structural magnesium alloys.Solute atoms and second phases can improve mechanical properties,but are deteriorating the heat dissipation performance.Through experimental determination of alloys,it is found that REMg12 phases have fewer negative impacts on thermal diffusivities thanτ;phases.With the same intermetallic compound,the solute atom Zn have more negative influences on thermal diffusivities of Mg-Zn-La/Ce alloys than the content of second phases.In order to quantitatively evaluate thermal conductivities and further design Mg alloys with both high strength and high thermal conductivity,a calculated method is provided to describe the thermal diffusivity of alloys as a function of alloy composition and phase constitution.A set of parameters for expression of thermal diffusivity of Mg-Zn-La/Ce alloys were obtained through assessing the experimental data.The thermal conductivities of Mg-Zn-La/Ce system were predicted and agreed well with experimental values with calculation error of 1.6%and standard error of±3.0 W/(m K).The calculation method considering thermal diffusivity resistivity improves the calculation accuracy and would be physically significant.
基金supported by the National Natural Science Foundation of China(51401200)Natural Science Foundation of Jilin Province(20140520099JH)+4 种基金National Science & Technology Pillar Program(2012BAE01B04)Chinese Academy of Sciences of Western Action Plan Project(KZCX2-XB3-06)the National Natural Science Foundation of China Major Project(91122030)National High Technology Research and Development Program of China(2011AA03A407)National Natural Science Foundation for Creative Research Group(20921002)
文摘The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the as-cast alloy and restrain grain growth during solution treatment, which was derived from the constitutional supercooling during solidification process and the formation of stable intermetallic compounds Ce Mg12 and Mg17La2. Furthermore, Ce/La microalloying and solution treatment resulted in an evolution from the original lamellar Ca2Mg6Zn3/α-Mg to the divorced eutectic structure. The thermal stability of Mg-Zn-Ca alloy could be effectively improved by Ce/La addition, because the low-melting-point binary Mg-Zn phase was transformed to Mg x Zn y-Ca-（Ce/La） phase with higher thermal stability and the amount of Ca2Mg6Zn3/α-Mg eutectic structure was reduced.
