The microstructure and mechanical properties of Mg-6Al-1.2Y-0.9Nd magnesium alloy with Sb, Sm, or Sn addition were investigated through X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microsco...The microstructure and mechanical properties of Mg-6Al-1.2Y-0.9Nd magnesium alloy with Sb, Sm, or Sn addition were investigated through X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The results show that small amounts of Sb, Sm, and especially Sn can refine the grains of the alloy. High melting point Sb3Y5, Al2Sm, and Nd5Sn3 intermetallic compounds can be formed respectively when Sb, Sm, and Sn are added to the alloy. Sb and Sm can improve the tensile strength of the alloy at ambient and elevated temperatures. The tensile strength of the alloy with Sm addition is the highest at 293 and 423 K. However, the tensile strength of the alloy with Sn addition is the highest at 448 K.展开更多
To further increase the mechanical properties, 0.5wt.% Sm was introduced to a Mg-10Y alloy in this study. The effects of Sm addition on the microstructures and mechanical properties of the Mg-10Y alloy, especially the...To further increase the mechanical properties, 0.5wt.% Sm was introduced to a Mg-10Y alloy in this study. The effects of Sm addition on the microstructures and mechanical properties of the Mg-10Y alloy, especially the aged Mg-10Y alloy, were investigated. The microstructure observation and tensile tests were performed by using an optical microscopy, a scanning electron microscopy and a universal material testing machine, respectively. The phase analysis was performed using X-ray diffractometer. The results show that the 0.5wt.% Sm addition can not only promote the formation of fine and dispersed Mg24Y5 phases, but also improve their morphology and distribution; it also increases the thermal stability of Mg24Y5 phases. Sm addition is seen to increase the ultimate tensile strength of Mg-10Y alloy at elevated temperatures(200, 250, 300 and 350 ℃), while decrease the elongation. But the elongation is still up to 7.5% even at 350 ℃. In the range of 250 ℃ to 300℃, the ultimate tensile strength of the alloy reaches its maximum(with a range average of 235 MPa) and is not sensitive to the temperature change, which is very useful to the application of heat-resistant magnesium alloys. Even at 350 ℃, the ultimate tensile strength of Mg-10Y-0.5Sm is still up to 155 MPa. Considering both of the ultimate tensile strength and elongation, the maximum application temperature of the Mg-10Y-0.5Sm alloy can be up to 300 ℃. The strengthening mechanisms of Mg-10Y-0.5Sm alloy are mainly attributed to dispersion strengthening of Mg24Y5 phase particles with a certain solubility of Sm and grain refinement strengthening of α-Mg matrix.展开更多
The effects of rare earth(RE) elements Y and Nd on the microstructure and mechanical properties of Mg-6Al magnesium alloy were investigated.The results show that a proper level of RE elements can obviously ref ine the...The effects of rare earth(RE) elements Y and Nd on the microstructure and mechanical properties of Mg-6Al magnesium alloy were investigated.The results show that a proper level of RE elements can obviously ref ine the microstructure of Mg-6Al magnesium alloys,reduce the quantity of β-Mg17Al12 phase and form Al2Y and Al2Nd phases.The combined addition of Y and Nd dramatically enhances the tensile strength of the alloys in the temperature range of 20-175℃.When the content of RE elements is up to 1.8%,the values of tensile strength at room temperature and at 150℃ simultaneously reach their maximum of 253 MPa and 196 MPa,respectively.The main mechanisms of enhancement in the mechanical properties of Mg-6Al alloy with Y and Nd are the grain ref ining strengthening and the dispersion strengthening.展开更多
镁合金具有比强度高、比刚度高、质量轻、切削性能好等优点,在航空航天、汽车制造及医疗服务等领域有着广泛的应用前景,但其绝对强度低,塑性差,限制了镁合金在一些领域的应用。为了改善镁合金综合性能,研究发现在镁合金中按一定比例加...镁合金具有比强度高、比刚度高、质量轻、切削性能好等优点,在航空航天、汽车制造及医疗服务等领域有着广泛的应用前景,但其绝对强度低,塑性差,限制了镁合金在一些领域的应用。为了改善镁合金综合性能,研究发现在镁合金中按一定比例加入稀土元素与过渡族元素后,会出现一种长周期有序堆垛结构(Long Period Stacking Ordered,简称LPSO相),LPSO相具有高硬度、高抗蠕变性能、高弹性模量等优点,能够同时改善合金的强度和塑性,因此,LPSO相引起了广大研究人员的关注。本文综述了稀土镁合金中LPSO相的研究进展,全面分析了LPSO相的类型及原子排布,讨论了LPSO相的形成机制和规律,以及LPSO相对合金性能的影响机制,评述了通过第一性原理对LPSO相晶体结构、弹性模量和LPSO相与层错能间关系的研究,最后对含LPSO相稀土镁合金的未来发展做出展望。展开更多
文摘The microstructure and mechanical properties of Mg-6Al-1.2Y-0.9Nd magnesium alloy with Sb, Sm, or Sn addition were investigated through X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The results show that small amounts of Sb, Sm, and especially Sn can refine the grains of the alloy. High melting point Sb3Y5, Al2Sm, and Nd5Sn3 intermetallic compounds can be formed respectively when Sb, Sm, and Sn are added to the alloy. Sb and Sm can improve the tensile strength of the alloy at ambient and elevated temperatures. The tensile strength of the alloy with Sm addition is the highest at 293 and 423 K. However, the tensile strength of the alloy with Sn addition is the highest at 448 K.
基金financially supported by the National Natural Science Foundation of China(No.51171059)the Innovative Research Team(in Science and Technology)in University of Henan Province(No.2012IRTSTHN008)the Basic and Frontier Technologies Research Plan of Henan Province(No.102300410018)
文摘To further increase the mechanical properties, 0.5wt.% Sm was introduced to a Mg-10Y alloy in this study. The effects of Sm addition on the microstructures and mechanical properties of the Mg-10Y alloy, especially the aged Mg-10Y alloy, were investigated. The microstructure observation and tensile tests were performed by using an optical microscopy, a scanning electron microscopy and a universal material testing machine, respectively. The phase analysis was performed using X-ray diffractometer. The results show that the 0.5wt.% Sm addition can not only promote the formation of fine and dispersed Mg24Y5 phases, but also improve their morphology and distribution; it also increases the thermal stability of Mg24Y5 phases. Sm addition is seen to increase the ultimate tensile strength of Mg-10Y alloy at elevated temperatures(200, 250, 300 and 350 ℃), while decrease the elongation. But the elongation is still up to 7.5% even at 350 ℃. In the range of 250 ℃ to 300℃, the ultimate tensile strength of the alloy reaches its maximum(with a range average of 235 MPa) and is not sensitive to the temperature change, which is very useful to the application of heat-resistant magnesium alloys. Even at 350 ℃, the ultimate tensile strength of Mg-10Y-0.5Sm is still up to 155 MPa. Considering both of the ultimate tensile strength and elongation, the maximum application temperature of the Mg-10Y-0.5Sm alloy can be up to 300 ℃. The strengthening mechanisms of Mg-10Y-0.5Sm alloy are mainly attributed to dispersion strengthening of Mg24Y5 phase particles with a certain solubility of Sm and grain refinement strengthening of α-Mg matrix.
文摘The effects of rare earth(RE) elements Y and Nd on the microstructure and mechanical properties of Mg-6Al magnesium alloy were investigated.The results show that a proper level of RE elements can obviously ref ine the microstructure of Mg-6Al magnesium alloys,reduce the quantity of β-Mg17Al12 phase and form Al2Y and Al2Nd phases.The combined addition of Y and Nd dramatically enhances the tensile strength of the alloys in the temperature range of 20-175℃.When the content of RE elements is up to 1.8%,the values of tensile strength at room temperature and at 150℃ simultaneously reach their maximum of 253 MPa and 196 MPa,respectively.The main mechanisms of enhancement in the mechanical properties of Mg-6Al alloy with Y and Nd are the grain ref ining strengthening and the dispersion strengthening.
文摘镁合金具有比强度高、比刚度高、质量轻、切削性能好等优点,在航空航天、汽车制造及医疗服务等领域有着广泛的应用前景,但其绝对强度低,塑性差,限制了镁合金在一些领域的应用。为了改善镁合金综合性能,研究发现在镁合金中按一定比例加入稀土元素与过渡族元素后,会出现一种长周期有序堆垛结构(Long Period Stacking Ordered,简称LPSO相),LPSO相具有高硬度、高抗蠕变性能、高弹性模量等优点,能够同时改善合金的强度和塑性,因此,LPSO相引起了广大研究人员的关注。本文综述了稀土镁合金中LPSO相的研究进展,全面分析了LPSO相的类型及原子排布,讨论了LPSO相的形成机制和规律,以及LPSO相对合金性能的影响机制,评述了通过第一性原理对LPSO相晶体结构、弹性模量和LPSO相与层错能间关系的研究,最后对含LPSO相稀土镁合金的未来发展做出展望。
