检索结果-南通市图书馆

dynamic recrystallization kinetics of as-cast az91d alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2014年第6期24卷 1683-1689页

作者：徐岩胡连喜孙宇哈尔滨工业大学材料科学与工程学院哈尔滨150001 北华大学机械工程学院吉林132021

The flow behavior and dynamic recrystallization（dRX） behavior of an as-cast az91 d alloy were investigated systematically by applying the isothermal compression tests in temperature range of 220-380 ℃ and strain rate range of 0.001-1 s^-*** effect of temperature and strain rate on the dRX behavior was *** results indicate that the nucleation and growth of dynamic recrystallized grains easily occur at higher temperatures and lower strain *** evaluate the evolution of dynamic recrystallization,the dRX kinetics model was proposed based on the experimental data of true stress-true strain *** was revealed that the volume fraction of dynamic recrystallized grains increased with increasing strain in terms of S-curves.A good agreement between the proposed dRX kinetics model and microstructure observation results validates the accuracy of dRX kinetics model for az91 d alloy.

关键词： az91d magnesium alloy compression flow behavior dynamic recrystallization behavior kinetics model

Initial corrosion behaviors of az91 magnesium alloy in the presence of SO_2

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第5期11卷 433-441页

作者： CuiLin XiaogangLi CorrosionandProtectionCenter KeyLaboratoryforCorrosionErosionandSurfaceTechnologyofBeijingUniversityofScienceandTechnologyBeijingBeijing100083China StateKeyLaboratoryforCorrosionandProtection InstituteofMetalResearchTheChineseAcademyofSciencesShenyang110016China

The effects of SO_2 on the initial atmospheric corrosion of az91d magnesiumalloy were investigated in laboratory. Met-allographic observation, SEM (Scanning ElectronMicroscopy), XRd (X-ray diffraction) and XPS (X-ray Proton Spectrograph) were used to analyze anddiscuss the initial surface morphology of corrosion layers and corrosion products. The corrosionrate of the alloy increases with increasing the content of SO_2. The initial attack has thecharacteristics of localized corrosion and preferentially concentrates on a phase. MgO and Mg(OH)_2form at first, which provide a protective layer, then the existence of SO_2 decreases the pH of thethin solution on the alloy, accelerates dissolution process, and promotes the formation of MgSO_3centre dot 6H_2O and MgSO_4 centre dot 6H_2O, meanwhile cracks were found on the corrosion productswith corrosion continuation. These soluble corrosion products and the cracks provide the paths forfiltering oxygen and corrosion pollutants into the matrix, which results in severe localizedcorrosion and the loss of protective function of film.

关键词： az91d magnesium alloy SO_2 initial stages atmospheric corrosion

Fabrication of a novel Mg-RE(Nd,Ce) intermetallic compound coating by molten salt diffusion and its effect on corrosion resistance of magnesium alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2016年第7期34卷 731-735页

作者：韩宝军古东懂何琼张小联彭光怀杨初斌 Jiangxi Provincial Engineering Research Center for magnesium alloys Gannan Normal University School of Chemistry and Chemical Engineering Gannan Normal University

A novel Mg-rare earth （Nd, Ce） coating containing intermetallic compound was fabricated on the surface of the az91d magnesium alloy by bathing the sample in a NaC1-KC1-LiC1-NdC13-CeC13 molten salt. The cross-sectional morphology, microstructure and phase composition of the coating were investigated by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and energy dispersive spectroscopy （EdS）. The corrosion resistance was characterized by the potentiodynamic polariza- tion curves. The SEM observation indicated that a continuous and compact diffusion coating was obtained on the surface of SMATed az91d magnesium alloy and the XRd and TEM investigations revealed that the new phases were Al2Ce and A12Nd intermetallic. The potentiodynamic polarization curves showed that the Mg-RE coating improved the corrosion resistance of the az91d magnesium alloy, and the corrosion current density of the coated sample was about 1510 mA/cm2 lower than the uncoated sample.

关键词： intermetallic compounds az91d magnesium alloy corrosion rare earth molten salts

Effect of coolant inhibitors on az91d

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2004年第3期23卷 255-259页

作者： I.M.Baghni WUYinshun ZHANGWei LIJiuqing MechanicalEngineeringdepatartment EngineeringCollegeofTajouraLibya CorrosionandProtectionCenter UniversityofScienceandTechnologyBeijingBeijing100083China

The inhibition effects of sodium vanadate along with inorganic coolantinhibitors were examined on corrosion of az91d in ASTM d1384-80 corrosive water by polarizationmeasurements. The galvanic corrosion of az91d coupled to 3003, 6063, and 356 Al alloys were alsotested. An effective combination of inhibitors containing (but not limited to) sodium vanadate,silicate, and nitrate was proposed for inhibition of az91d and prevention of galvanic corrosion.

关键词： failure and protection of materials inhibitors potentiodynamicpolarization coolant az91d magnesium alloy

Preparation and performance of coating on rare-earth compounds-immersed magnesium alloy by micro-arc oxidation

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2012年第7期22卷 1647-1654页

作者：刘峰李玉洁顾佳婧严青松罗强蔡启舟华中科技大学材料成形与模具技术国家重点实验室武汉430074 南昌航空大学轻合金加工科学与技术国防重点学科实验室南昌330063

A composite ceramic coating containing Y2O3-ZrO2-MgO（YSZ-MgO） was prepared on az91d magnesium alloy,which was immersed in Y（NO3）3 aqueous solution as pretreatment,by micro-arc oxidation（MAO） *** morphology,elemental and phase compositions,corrosion behavior and thermal stability of the coatings were studied by SEM,EdX,XRd,electrochemical corrosion test,high temperature oxidation and thermal shock *** results show that the coating mainly consists of ZrO2,Y2O3,MgO,Mg2SiO4,and *** these compounds,Y2O3 accounts for 26.7% of（Y2O3 ＋ ZrO2）.The thickness of YSZ-MgO coating is smaller than that of ZrO2-MgO coating,but its compactness and surface roughness are better than those of ZrO2-MgO ***-MgO coating has a good corrosion resistance,and its corrosion rate in 5% NaCl aqueous solution is lower than that of ZrO2-MgO and only about 8.5% of that of az91d magnesium *** oxidation at 410 °C,the mass gain of az91d magnesium alloy presents a linear increase with the oxidation *** YSZ-MgO coating and ZrO2-MgO coating can remarkably decrease the oxidation mass *** oxidation mass gain of YSZ-MgO coating is lower than that of ZrO2-MgO coating,especially during a long oxidation *** thermal shock resistance of YSZ-MgO coating is superior to ZrO2-MgO coating.

关键词： az91d magnesium alloy micro-arc oxidation(MAO) Y2O3-ZrO2-MgO composite coating corrosion behavior thermal stability