Ultrasonic vibration was introduced into the Mg-8Li-3A1 alloy melt during its solidification process. The microstructure, corrosion resistance and mechanical properties of the Mg-8Li-3A1 alloy under ultrasonic vibrati...Ultrasonic vibration was introduced into the Mg-8Li-3A1 alloy melt during its solidification process. The microstructure, corrosion resistance and mechanical properties of the Mg-8Li-3A1 alloy under ultrasonic vibration were investigated. The experiment results show that the morphology of a phase is modified from coarse rosette-like structure to fine globular one with the application of ultrasonic vibration. The fine globular structure is obtained especially when the power is 170 W, and the refining effect also gets better with prolonging the ultrasonic treatment time. The corrosion resistance of the alloy with 170 W of ultrasonic vibration for 90 s is improved apparently compared with the alloy without ultrasonic vibration. The mechanical properties of alloys with ultrasonic vibration are also both improved apparently. The tensile strength and elongation of alloy improve by 9.5% and 45.7%, respectively, with 170 W of ultrasonic treatment for 90 s.展开更多
Microstructures and mechanical properties of LZ83?xY alloys containingI-phase andW-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content ofI-phase andW-phase changes by varyin...Microstructures and mechanical properties of LZ83?xY alloys containingI-phase andW-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content ofI-phase andW-phase changes by varying Zn/Y mass ratio in the LZ83?xY alloys. The cohesion ofI-phase/α-Mg eutectic pockets can enhance the strength in the as-cast LZ83?0.5Y and LZ83?1.0Y alloys, while theW-phase has no obvious strengthening effect on the LZ83?1.5Y alloy. In the extruded alloys, the I-phase andW-phase were extruded into the particles with nanoscale size in theβ-Li matrix phase. The dispersion strengthening of W-phase was more obvious because of the higher volume fraction. The ultimate tensile strength of extruded LZ83?1.5Y alloy is up to 238 MPa while the elongation is up to 20%.展开更多
The corrosion behavior of Mg-8Li-3Zn-Al alloy was investigated in neutral 3.5%NaCl aqueous solution by morphology observation and electrochemical tests.The weight loss method was to measure the corrosion rate.The elec...The corrosion behavior of Mg-8Li-3Zn-Al alloy was investigated in neutral 3.5%NaCl aqueous solution by morphology observation and electrochemical tests.The weight loss method was to measure the corrosion rate.The electrochemical results indicated that the corrosion resistance of Mg-8Li-3Zn-Al alloy in 3.5%NaCl solution is poorer than that in distilled water.The Cl-anion leads to the initiation and development of the corrosion pits.And the corrosion products are mainly Mg(OH)_(2).展开更多
Mg-8Li-3Al-xCe(x=0, 1.0, 3.0) alloys were prepared. And the effects of cerium content on the microstructure and mechanical properties were studied. Results show that the as-cast alloy is composed of α(Mg), β(Li) and...Mg-8Li-3Al-xCe(x=0, 1.0, 3.0) alloys were prepared. And the effects of cerium content on the microstructure and mechanical properties were studied. Results show that the as-cast alloy is composed of α(Mg), β(Li) and Al2Ce. Cerium has obvious refining effect on α(Mg). And the strength and elongation of alloys were improved.展开更多
PeniciUium purpurogenum Li-3, a fungus producing β-glucuronidase （PGUS）, can con- vert glycyrrhizin （GL） to glycyrrhetinic acid monoglucuronide （GAMG） when grown in medium with GL as the sole carbon source. In ...PeniciUium purpurogenum Li-3, a fungus producing β-glucuronidase （PGUS）, can con- vert glycyrrhizin （GL） to glycyrrhetinic acid monoglucuronide （GAMG） when grown in medium with GL as the sole carbon source. In order to improve the conversion rate of GL and the yield of GAMG, licorice extract （LE） was added as an inducer to enhance the production of GAMG by the PGUS. In this work, the influence of LE on the conversion rate of GL to GAMG was studied. When the Penicil- lium purpurogenum Li-3 was grown in the medium containing LE and GL （ concentration ratio of LE to GL was 2： 3）, the conversion rate of GL was 84. 12% with 38. 18% increase and the yield of GAMG was 80. 47% with 37. 18% increase, comparing with to the medium only containing GL at 48 h. The enzyme activity of ^-glucuronidase was also enhanced from 22. 4 U/mL to 82.3 U/mL, which in- creased up to about 3. 67 fold. The results showed that LE could significantly improve the induced expression level of PGUS.展开更多
基金Project(2009AA03Z525)supported by the High-tech Research and Development Program of ChinaProject(NCET-08-0080)supported by the Program of New Century Excellent Talents of the Ministry of Education of China+1 种基金Project(20082172)supported by the Natural Science Fund of Liaoning Province,ChinaProject(2009J21DW003)supported by the Science and Technology Fund of Dalian City,China
文摘Ultrasonic vibration was introduced into the Mg-8Li-3A1 alloy melt during its solidification process. The microstructure, corrosion resistance and mechanical properties of the Mg-8Li-3A1 alloy under ultrasonic vibration were investigated. The experiment results show that the morphology of a phase is modified from coarse rosette-like structure to fine globular one with the application of ultrasonic vibration. The fine globular structure is obtained especially when the power is 170 W, and the refining effect also gets better with prolonging the ultrasonic treatment time. The corrosion resistance of the alloy with 170 W of ultrasonic vibration for 90 s is improved apparently compared with the alloy without ultrasonic vibration. The mechanical properties of alloys with ultrasonic vibration are also both improved apparently. The tensile strength and elongation of alloy improve by 9.5% and 45.7%, respectively, with 170 W of ultrasonic treatment for 90 s.
基金Project(2007CB613702)supported by the National Basic Research Program of ChinaProject(CDJZR14130007)supported by the Fundamental Research Funds for the Central Universities,China
文摘Microstructures and mechanical properties of LZ83?xY alloys containingI-phase andW-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content ofI-phase andW-phase changes by varying Zn/Y mass ratio in the LZ83?xY alloys. The cohesion ofI-phase/α-Mg eutectic pockets can enhance the strength in the as-cast LZ83?0.5Y and LZ83?1.0Y alloys, while theW-phase has no obvious strengthening effect on the LZ83?1.5Y alloy. In the extruded alloys, the I-phase andW-phase were extruded into the particles with nanoscale size in theβ-Li matrix phase. The dispersion strengthening of W-phase was more obvious because of the higher volume fraction. The ultimate tensile strength of extruded LZ83?1.5Y alloy is up to 238 MPa while the elongation is up to 20%.
基金This work was supported by the financial support of the National Natural Science Foundation of China(No.41276074)National Research Program of China(No.2014CB643304).
文摘The corrosion behavior of Mg-8Li-3Zn-Al alloy was investigated in neutral 3.5%NaCl aqueous solution by morphology observation and electrochemical tests.The weight loss method was to measure the corrosion rate.The electrochemical results indicated that the corrosion resistance of Mg-8Li-3Zn-Al alloy in 3.5%NaCl solution is poorer than that in distilled water.The Cl-anion leads to the initiation and development of the corrosion pits.And the corrosion products are mainly Mg(OH)_(2).
基金Project supported by Heilongjiang Province Key Technologies R&D Project (GC06A212)
文摘Mg-8Li-3Al-xCe(x=0, 1.0, 3.0) alloys were prepared. And the effects of cerium content on the microstructure and mechanical properties were studied. Results show that the as-cast alloy is composed of α(Mg), β(Li) and Al2Ce. Cerium has obvious refining effect on α(Mg). And the strength and elongation of alloys were improved.
基金Supported by the National Science Foundation of China(21276024,21276025)National High-Tech Research and Development Program of China("863"Program)(2012AA02A704)
文摘PeniciUium purpurogenum Li-3, a fungus producing β-glucuronidase （PGUS）, can con- vert glycyrrhizin （GL） to glycyrrhetinic acid monoglucuronide （GAMG） when grown in medium with GL as the sole carbon source. In order to improve the conversion rate of GL and the yield of GAMG, licorice extract （LE） was added as an inducer to enhance the production of GAMG by the PGUS. In this work, the influence of LE on the conversion rate of GL to GAMG was studied. When the Penicil- lium purpurogenum Li-3 was grown in the medium containing LE and GL （ concentration ratio of LE to GL was 2： 3）, the conversion rate of GL was 84. 12% with 38. 18% increase and the yield of GAMG was 80. 47% with 37. 18% increase, comparing with to the medium only containing GL at 48 h. The enzyme activity of ^-glucuronidase was also enhanced from 22. 4 U/mL to 82.3 U/mL, which in- creased up to about 3. 67 fold. The results showed that LE could significantly improve the induced expression level of PGUS.
