Effect of heat treatments on tensile properties and microstructures of wrought Mg−Zn−Zr-RE alloys

The effect of heat treatments on the tensile properties and microstructures of wrought Mg–Zn–Zr-Rare earth alloys MB25 and MB26 have been studied in this paper. It was shown that the homogenization of the cast ingots decreased the strength of the extruded bars because some grain boundary phases were dissolved during the process of this treatment, while the ageing treatment of the extruded bars increased the strength due to the dispersive precipitation of MgZn₂ phase. The quenching + ageing treatments of the extruded bars decreases the strength and plasticity because of the growing up of the grains.Abbreviations ED electron diffraction - GB grain boundary - RE rare earth - TEM transmission electron microscope     

Hydrogen Absorption and Release Behavior in Hydrogen Decrepitation Process of Nd-Fe-B Alloys

The behavior of hydrogen absorption and release in hydrogen decrepitation (HD) process of Nd-Fe-B alloys were investigated. The results reveal that the reactivity and the amount of hydrogen absorption in HD process are related to the surface activity of the alloy so that the fresh and active surface has a higher efficiency. The presence of Nd-rich phase at the grain boundary is an essential factor of the HD activity of the alloy at room temperature. On degassing, hydrogen is released from the HD powder continuously with increasing temperature. And the residual hydrogen is as low as 0.0015% at 1073K, which shows that the hydrogen is almost exhaused. It is feasible to remove the hydrogen from the HD powder by heating treatment at the temperature of 523-723K for 1h prior to the magnetic field forming in order to decrease the harmful effect of hydrogen on the easy axis alignment of HD magnet.     

退火损伤对Er注入GaAs和Yb注入InP发光的影响

本文报道了CaAs∶Er、InP∶Yb发光样品的二次离子质谱、X-射线双晶衍射测量结果及其与Er离子的表面成份的关系.分析讨论了退火损伤对GaAs∶Er和InP∶Yb发光的影响以及Er~(3+)复合体发光中心模型.     

用φ20mm离心萃取器两步法制取高纯钇

本文研究了中钇富镧稀土的氧化物溶液在环烷酸中的萃取行为，测定了镧钇组成、温度变化与分离系数的关系；在Ｐ＿（５０７）体系中研究了ｐＨ值与分配比的关系；提出用环烷酸、Ｐ＿（５０７）两种萃取剂制备高纯钇的工艺流程。用８４台φ２０ｍｍ离心萃取器进行了一个月的台架试验，结果证明两种萃取剂有很好的互补性，在满足钇的纯度要求下有较高收率。离心萃取器具有易分相、体系存留量少、液流密闭性好等优点，它更适宜于粘度大、级数多、产品纯度要求高的体系。     

挡土墙填土曲线破裂面的地震主动土压力分析

在地震作用影响下，墙后填土处于极限平衡状态时，假定破裂面为一条通过墙趾的旋轮线。从墙后土楔中取出一微薄水平层，研究其在水平惯性力下的平衡，得到的地震土压力分布和土压力合力作用点位置均与实验结果相吻合。     

稀土混合物水溶液中囊泡的形成

依据柠檬酸的螯合作用和乙二醇的空间位阻效应，获得了稀土混合物囊泡。并利用ＩＣＰ、ＴＥＭ、ＦＳ等仪器对囊泡的性能进行了研究，最后对囊泡的形成机理进行了讨论。     

小浪底斜心墙堆石坝的地震反应分析

采用等价粘弹性动力有限元模型，结合有效应力法，对黄河小浪底斜心墙堆石坝最终设计断面在淤积后期受地震作用的动力特性进行了分析。分析时考虑了淤积土体内有未消散的超静孔压。结果表明明，坝体受里氏６．５级地震时，下游坝基及上游淤土表层均有一定范围的液化区，由于坝基液化区距坝体较远，因而只影响到坝趾压戗的局部；当坝体受里氏８级地震时，坝趾下游近处的坝基沙砾石处于液化状态，上游库区淤土有较大较范围的液化区，在     

WTG420铁路罐车用钢的组织结构和力学性能分析

分析了ＷＴＧ４２０铁路罐车用钢的组织结构和力学性能。提出了冶炼与轧制的技术关键，其一，添加稀土元素改善钢中夹杂物；其二，采用控轧控冷使铁素体晶粒细化。     

Role of RE and Mg on Graphitization of Spheroidal Graphite Malleable Cast Iron

ＲｏｌｅｏｆＲＥａｎｄＭｇｏｎＧｒａｐｈｉｔｉｚａｔｉｏｎｏｆＳｐｈｅｒｏｉｄａｌＧｒａｐｈｉｔｅＭａｌｌｅａｂｌｅＣａｓｔＩｒｏｎ￥ＬｉｕＪｉｎ－Ｈａｉ（ＨｅｂｅｉＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｔｏｇｙ，Ｍｉａｎｊｉｎ３００１３０，Ｃｈｉｎａ）...     

含钇奥氏体基堆焊焊条堆焊层研究

针对高温、磨损、热疲劳工况下服役零件的失效，研制了一种含稀土元素钇的奥氏体基沉淀强化型堆焊焊条，并对堆焊层组织与性能进行了较系统的研究。