Mg2Ni1-xCux (x=0, 0.2, 0.4)合金熔炼法加球磨处理后的储氢性能

采用熔炼法加球磨处理制备Mg2Ni1-xCux(x=0,0.2,0.4)合金。通过XRD和SEM/EDX对合金的相成分和微观组织进行分析。研究表明,3种合金中都有Mg2Ni相形成。随着Cu含量的增加,合金分别形成Mg2Cu相和Cu11Mg10Ni9相。PCT测量结果表明,Cu的添加可以改善合金的吸放氢性能。     

Influence of impurities on microstructure and mechanical properties of ZK60 magnesium alloy

The influence of impurity content on the microstructure and mechanical properties of ZK60 magnesium alloys was investigated by optical microscopy, scanning electron microscopy and tensile test. ZK60 alloys were prepared by changing holding time of alloy melt during semi-continuous casting in order to control the content of impurity elements. The alloy with lower purity content is found to have less second precipitates and larger grain size in the as-cast state. However, in the as-extruded state, reducing impurities brings about a decrease in grain size and an increase in yield strength from 244 MPa to 268 MPa, while the elongations in the as-extruded alloys with different contents of impurities are almost the same. After T5 treatment, impurity content is found to have more obvious effect on the yield strength of ZK60 alloy. The yield strength of ZK60-45 alloys with low impurity content is increased up to 295 MPa after T5 treatment.     

Influence of impurities on damping properties of ZK60 magnesium alloy

The influence of impurities on damping capacities of ZK60 magnesium alloys in the as-cast, as-extruded and T4-treated states was investigated by dynamically mechanical analyzer at room temperature. Granato and Lucke dislocation pinning model was employed to explain damping properties of the alloys. It is found that reducing impurity content can decrease the amount of second-phase particles, increase grain size and improve damping capacity of the as-cast alloy slightly. The as-extruded alloy with lower impurity content is found to possess obviously higher damping capacity in the relatively high strain region than that with higher impurity concentration, which appears to originate mainly from different dislocation characteristics. The variation tendency of damping property with change of impurity content after solution-treatment is also similar to that in the as-extruded and as-cast states. Meanwhile, the purification of the alloy results in an evident improvement in tensile yield strength in the as-extruded state.     

Comparison of as-cast microstructure,tensile and creep properties for Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys

The as-cast microstructure,tensile and creep properties of Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys were investigated and compared by using optical microscopy and scanning electron microscopy,X-ray diffraction analysis and tensile tests. The results indicate that the as-cast microstructures of Mg-3Sn-1Ca and Mg-3Sn-2Ca alloys are different.The former is mainly composed ofα-Mg,eutectic CaMgSn and solid state precipitation of Mg 2 Sn,whereas the latter is mainly composed ofα-Mg, primary CaMgSn,eutectic CaMgSn and Mg2Ca phases.As a result,the two alloys obtain different tensile and creep properties. Mg-3Sn-1Ca alloy shows relatively higher ultimate tensile strength and elongation at room temperature and 150℃than Mg-3Sn-2Ca alloy,however,the yield strengths of Mg-3Sn-1Ca alloy at room temperature and 150℃are relatively low.In addition,the creep properties of Mg-3Sn-1Ca alloy at 150℃and 70 MPa for 100 h are obviously lower than those of the Mg-3Sn-2Ca alloy.     

Numerical and physical simulation of new SPD method combining extrusion and equal channel angular pressing for AZ31 magnesium alloy

A new serve plastic deformation(SPD) including initial forward extrusion and subsequent shearing process(ES) was proposed.The influence of the ES forming on the grain refinement of the microstructure was researched.The components of ES forming die were manufactured and installed to Gleeble1500D thermo-mechanical simulator.The microstructure observations were carried out on the as-extruded rods(as-received) and ES formed rods.From the simulation results,ES forming can increase the cumulative strain enormousl...     

高硅铝合金标准样品的热变形行为

对高硅铝合金光谱标准样品在应变速率为0.01～1s-1、变形温度为350～500℃条件下的热压缩变形行为进行实验研究。结果表明:高硅铝合金热压缩变形中发生了明显的动态回复与动态再结晶,流变应力随应变速率的增加而增加,随温度的增加而降低;通过线性回归分析计算出高硅铝合金材料的应变硬化指数n以及变形激活能Q,获得了高硅铝合金高温条件下的流变应力本构方程;研究工艺参数(变形温度t、应变速率ε)对晶粒尺寸的影响,确定最佳工艺参数:t=400℃,ε=0.1s-1。     

反应磁控溅射沉积工艺对Cr-N涂层微观结构的影响

研究在不同工艺条件下用直流反应磁控溅射技术在T10衬底上制备Cr-N涂层,并采用光电子能谱仪和XRD依次分析Cr-N涂层的表面结构和工艺参数对Cr-N涂层成分及相组成的影响。结果表明,Cr-N涂层在存放一段时间后表面产生复杂的Cr2O3相以及Cr（O2 N）x相;常温下随着N2含量的增加,涂层相结构逐渐由Cr转变为化学比的CrN相。当N2含量为33-3％时,Cr-N涂层的相成分主要为Cr2N＋CrN。并发现衬底偏压直接影响Cr-N系涂层的晶态及取向特征,当偏压增加到-130V时,Cr-N涂层中β-Cr2N相结构逐渐转变为（110）和（300）取向结构。     

不同状态Mg-9Sr中间合金对AZ31镁合金铸态组织的影响

研究Mg-9Sr中间合金及其处理工艺对AZ31镁合金铸态组织的影响。结果表明：在AZ31镁合金中加入不同状态的Mg-9Sr中间合金（常规铸态、快速凝固态、固溶态和轧制态）对AZ31镁合金均有很好的晶粒细化效果,其中轧制态Mg-9Sr中间合金的细化效果最好,其次依次为固溶态、常规铸态和快速凝态Mg-9Sr中间合金。在Sr加入量0.1%和熔体保温时间80 min条件下,轧制态Mg-9Sr中间合金可使AZ31镁合金获得62 μm的最小平均晶粒尺寸。     

Twin-roll strip casting of magnesium alloys in China

The development status of twin-roll strip casting for magnesium alloys in China was summarized as well as the new progress when several kinds of twin-roll strip casting technologies were developed and used.Horizontal twin-roll casting (HTRC) of magnesium alloys has attracted much attention and has been industrialized in China.Vertical twin roll casting(VTRC) of the magnesium alloys can reach a speed of higher than 30 m/min and its research and development are just beginning and exhibit exciting potential...     

Effects of various Mg-Sr master alloys on microstructural refinement of ZK60 magnesium alloy

The effects of various Mg-Sr master alloys(conventional as-cast,rapidly-solidified,rolled and solutionized) on microstructural refinement of ZK60 magnesium alloy were investigated.The results indicate that the refinement efficiency of various Mg-Sr master alloys in ZK60 alloy is different.The rolled Mg-Srmaster alloy is found to have relatively higher refinement efficiency than the conventional as-cast,solutionized and rapidly-solidified Mg-Sr master alloys.After being treated with the rolled Mg-Sr maste...