The surface modification of magnesium alloys (AZ31 and AZ91HP) was studied by a high current pulsed elect ron beam( HCPEB) . The result s show that the cross2sectional microhardness of t reated samples increases not only in the heat affected zone ( HAZ) , but also beyond HAZ , reaching over 250μm. This is due to the action of quasi2static thermal st ress and the shock thermal st ress wave with materials , which result in it s fast deformation on the surface layer and so increases microhardness. For the AZ91HP alloy , a nearly complete dissolution of the inter2 metallic phase Mg17Al12 is observed , and a super2saturated solid solution forms on the re2melted surface , which is due to the solute t rapping effect during the fast solidification process. Measurement s on sliding wear show that wear resistance is improved by approximately 5. 6 and 2. 4 times for the AZ31 and AZ91HP respectively , as compared with as2received samples.

This paper reports an analysis of the microstructure and property modifications on a commercial Mg alloy AZ91HP treated by using High Current Pulsed Electron Beam (HCPEB). It is shown that, a thin layer consisting of nanograined MgO formed on the top surface after HCPEB (electron energy ∼30 keV, pulse duration 1 μs, energy density ∼3 J/cm2) treatment, below which is a melted layer with depth of about 8–10 μm. The heat affected zone (HAZ) underneath the melted layer and stress wave affected zone contains many stress induced deformation marks. Meantime, a nearly complete dissolution of the intermetallic phase Mg17Al12 in the melted layer is observed, leading to the formation of a supersaturated solid solution on the surface. This is due to the solute trapping effect occurred during the fast solidification process. As a result, the wear and corrosion resistance of the alloy were significantly improved as shown by sliding friction, wear and immersion tests.

The properties of boron carbide-lanthanum boride composite material prepared by hot pressed sintering method was tested, lanthanum boride as a sintering aid for boron carbide is investigated in this paper. The study shows: the hardness of boron carbide-lanthanum boride increases with the content of lanthanum boride. When the content of the lanthanum boride is 6wt%, the hardness reaches its supreme value of 31.83Gpa，its hardness is improved nearly 20.52% compared to monolithic boron carbide. The content of the lanthanum boride does not affect greatly on flexibility strength. However，it gives much effect on fracture toughness. The fracture toughness changes like the form of saw-toothed wave as the content of lanthanum boride increases in the test. When the content of the lanthanum boride is 6wt%, the fracture toughness reaches its supreme value of 5.14MPa.m1/2, which is improved nearly 39.67% compared to monolithic boron carbide materials. The fracture scanning electric microscope analysis of boron carbide-lanthanum boride composite material finds that, with the increasing the content of lanthanum boride, the interior station of monolithic boron carbide is changed. The crystallite arrangement is so compact that pores disappear gradually. The main fracture way of boron carbide-lanthanum boride composite material is intercrystalline rupture, while the transcrystalline rupture is minor, which is in accordance with fracture mechanism of ceramic material. It appears that this change of fracture mode by the addition of lanthanum boride gives rise to the improvement of the fracture toughness.

设定RE35%、Mg6-lO%、Ba4-8%、Si～40%。余量为铁（重量百分数）的稀土钡镁硅铁合金。测得该合金的密度为3.74-4.14g/cme3，其熔化温度范围为1050-1140℃。X射线衍射分析表明其主要物相为FeSi2、Mg2Si、FeSi、RESi2、BaSi2、si及新相Ba5.6Ce2.6si7Mg11。

在成分（wt%）为RE2.91、Ba3.85、Mg9.70、Ca2.2、Al1.5，余量为Fe的范围内，运用x-射线衍射分析及电子探针分析手段对REBaMgsiFe合金的物相和显微组织进行了分析，发现了稀土和碱土金属之间在硅基中的互溶现象并对其进行了初步鉴别。

用四川冕宁天然氟碳铈矿晶体为原料，研究其热分解过程。测定了粉状氟碳铈矿空气气氛下热分解过程的热重-差热曲线。根据Criado提出的反应动力学机制模型，采用热分析技术对动力学数据进行了处理和计算，绘制了氟碳铈矿粉末热分解反应的动力学曲线，与标准曲线比较，结合前期工作动力学参数计算的结果，确定了热分解过程的反应机制为形核和生长，其反应动力学模型的微分和积分形式的表达式分别为：f(α)=(1-α)和g(α)=-ln(1-α)。

采用63kVA直流矿热炉，对高磷稀土精矿直接进行碳热还原，制备高品位稀土硅化物合金。冶炼过程中生成的废渣很少，炉底不上涨，炉内碳热还原反应进行得较为彻底，稀土几乎全部进入产品合金当中。同时，对稀土精矿中的主要有害杂质磷在冶炼过程中及在矿热炉内的行为进行了深入的研究，提出了最大限度减少磷进入产品合金的策略。实验得到的稀土硅化物合金具有独特的组织结构，与众不同的抗水化性，其粉化特性也与传统观点有较大的差异。

利用x射线衍射、扫描电镜和电子探针等分析手段对碳热还原法稀土硅铁合金的物相及显微组织进行了分析，合金中的主要物相为Si，RESi2和FeSi2；对合金中的单质硅薄带网状结构。RE-Si2与si和RESi2与Fesi2两类共晶组织进行了较为详细的讨论。这三种组织形成了合金稳定的结构。同时对合金中的主要杂质元素Ca，Al和Ba的存在形式进行了初步鉴定，Ca主要以固溶态的形式存在，Al和Ba主要以化合物形式存在。在此基础上说明了显微组织结构对合金性能的影响。

采用X射线衍射、电子探针、热重分析及化学分析等方法研究了独居石精矿的C还原行为，考察了REPO4的分解过程。结果表明，在一定温度下，独居石精矿中的REPO4能被C分解为稀土氧化物，P以单质形式被还原挥发出去，其中CePO4的分解过程与LaPO4，NdPO4等的分解过程不同步。