Effects of two kinds of magnesium compound with fertilizer on Daylily （Hemerocallis citrina Baroni） growth, yield, and soil nutrients in red soil were studied. The results indicated that significant effects of magne...Effects of two kinds of magnesium compound with fertilizer on Daylily （Hemerocallis citrina Baroni） growth, yield, and soil nutrients in red soil were studied. The results indicated that significant effects of magnesium applied to soils were observed in increasing Daylily （Hemerocallis citrina Baroni） yield, improving its growth, and strengthening its antivirus property as well as increasing the amount of exchangeable Mg, N, P, and K in red soil. In particular, the effects of magnesium compound fertilizer Ⅱ （MCF2） with higher Mg content were better than that of the others, which increased Daylily （Hemerocallis citrina Baroni） yield by 57.4, 32.8, and 14.5% compared to that of control treatment （CK）, chemical fertilizer with nitrogen, phosphorus, potassium treatment （CF）, and magnesium compound fertilizer Ⅰ treatment （MCF1） with lower Mg content. It increased soil Alkali N, available P, exchangeable K, and exchangeable Mg by 94.9, 46.5, 31.1, and 35.3%, respectively, compared with that of CK treatment. Therefore, the application of magnesium compound with fertilizer is an optimum method for improving red soil quality.展开更多
Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properti...Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properties of welded samples by preventing the fracture location at the Mg/Al interface. Friction stir welding was performed to join Mg to Al at different rotational and travel speeds. The microstructure of the welded samples showed the IMCs layers containing Al12Mg17(γ) and Al3Mg2(β) at the welding zone with a thickness(< 3.5 μm). Mechanical properties were mainly affected by the thickness of the IMCs, which was governed by welding parameters. The highest tensile strength was obtained at 600 r/min and 40 mm/min with a welding efficiency of 80%. The specimens could fracture along the boundary at the thermo-mechanically affected zone in the Mg side of the welded joint.展开更多
Cerium conversion treatment was applied on magnesium coatings in a solution containing CeC13. The composition ot the cenum conversion layer on magnesium was investigated using X-ray photoelectron spectroscopy （XPS）,...Cerium conversion treatment was applied on magnesium coatings in a solution containing CeC13. The composition ot the cenum conversion layer on magnesium was investigated using X-ray photoelectron spectroscopy （XPS）, It was revealed that the composition predominately consisted of a three-valent state cerium compound with a relative abundance around 90%. Some of Ce^3＋ was oxidized to Ce^4＋. Electrochemical impedance spectroscopy results revealed that the total impedance of cerium-treated samples increased for a short immersion time in NaC1 solution before coating deteriorating. This deterioration was due to the coating porosity increasing and the breakdown of the conversion layer展开更多
The microstructures of cast magnesium alloys solified without electromagnetic field, under low-frequency magnetic field, and under magnetostatic field were compared. The results show that the grain is greatly refined ...The microstructures of cast magnesium alloys solified without electromagnetic field, under low-frequency magnetic field, and under magnetostatic field were compared. The results show that the grain is greatly refined when the magnesium alloy solidifies in the magnetostatic field, the thickness of boundary compound decreases, and much fine massive compound appears, therefore the forming property of magnesium alloy is improved.展开更多
Mg alloy AZ31B was welded to Al alloy 6061 by laser welding technique.The welded samples were exampled by metallographic techniques using both optical and scanning microscopy in combination with energy dispersive spec...Mg alloy AZ31B was welded to Al alloy 6061 by laser welding technique.The welded samples were exampled by metallographic techniques using both optical and scanning microscopy in combination with energy dispersive spectroscopy microanalysis(EDS).Compared with the TIG welding joint,the mechanism of joining dissimilar metal magnesium and aluminum by laser was analyzed.It is found that magnesium is swirled by laser and the weld pool forms down toward aluminum.The microstructure at the bottom of the molten pool was observed.The swirl made the continuous intermetallic compounds at the interface between Mg and Al more dispersive.But intermetallic compounds still existed using this high speed welding technique and reduced the joint strength.展开更多
文摘Effects of two kinds of magnesium compound with fertilizer on Daylily （Hemerocallis citrina Baroni） growth, yield, and soil nutrients in red soil were studied. The results indicated that significant effects of magnesium applied to soils were observed in increasing Daylily （Hemerocallis citrina Baroni） yield, improving its growth, and strengthening its antivirus property as well as increasing the amount of exchangeable Mg, N, P, and K in red soil. In particular, the effects of magnesium compound fertilizer Ⅱ （MCF2） with higher Mg content were better than that of the others, which increased Daylily （Hemerocallis citrina Baroni） yield by 57.4, 32.8, and 14.5% compared to that of control treatment （CK）, chemical fertilizer with nitrogen, phosphorus, potassium treatment （CF）, and magnesium compound fertilizer Ⅰ treatment （MCF1） with lower Mg content. It increased soil Alkali N, available P, exchangeable K, and exchangeable Mg by 94.9, 46.5, 31.1, and 35.3%, respectively, compared with that of CK treatment. Therefore, the application of magnesium compound with fertilizer is an optimum method for improving red soil quality.
基金supported by the National Natural Science Foundation of China (Nos.51601108,52071191)the Natural Science Foundation of Shandong Province,China (No.ZR2020ME011).
基金Universiti Kebangsaan Malaysia for supporting this research project through the research funding (AP-2015-016)
文摘Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properties of welded samples by preventing the fracture location at the Mg/Al interface. Friction stir welding was performed to join Mg to Al at different rotational and travel speeds. The microstructure of the welded samples showed the IMCs layers containing Al12Mg17(γ) and Al3Mg2(β) at the welding zone with a thickness(< 3.5 μm). Mechanical properties were mainly affected by the thickness of the IMCs, which was governed by welding parameters. The highest tensile strength was obtained at 600 r/min and 40 mm/min with a welding efficiency of 80%. The specimens could fracture along the boundary at the thermo-mechanically affected zone in the Mg side of the welded joint.
文摘Cerium conversion treatment was applied on magnesium coatings in a solution containing CeC13. The composition ot the cenum conversion layer on magnesium was investigated using X-ray photoelectron spectroscopy （XPS）, It was revealed that the composition predominately consisted of a three-valent state cerium compound with a relative abundance around 90%. Some of Ce^3＋ was oxidized to Ce^4＋. Electrochemical impedance spectroscopy results revealed that the total impedance of cerium-treated samples increased for a short immersion time in NaC1 solution before coating deteriorating. This deterioration was due to the coating porosity increasing and the breakdown of the conversion layer
文摘The microstructures of cast magnesium alloys solified without electromagnetic field, under low-frequency magnetic field, and under magnetostatic field were compared. The results show that the grain is greatly refined when the magnesium alloy solidifies in the magnetostatic field, the thickness of boundary compound decreases, and much fine massive compound appears, therefore the forming property of magnesium alloy is improved.
文摘Mg alloy AZ31B was welded to Al alloy 6061 by laser welding technique.The welded samples were exampled by metallographic techniques using both optical and scanning microscopy in combination with energy dispersive spectroscopy microanalysis(EDS).Compared with the TIG welding joint,the mechanism of joining dissimilar metal magnesium and aluminum by laser was analyzed.It is found that magnesium is swirled by laser and the weld pool forms down toward aluminum.The microstructure at the bottom of the molten pool was observed.The swirl made the continuous intermetallic compounds at the interface between Mg and Al more dispersive.But intermetallic compounds still existed using this high speed welding technique and reduced the joint strength.
