国外钛工业的发展和技术进步

金属钛是继铁和铝之后潜在增长的第三金属。钛工业始于第二次世界大战,是随着军备需要和作为战略物资发展起来的。全世界钛生产能力估计为10万吨。80年代末,对钛的需求量有所增长,预计90年代将保持增长势头。日本开发的10吨联合炉是克劳尔法工艺技术的显著进步。替代现行克劳尔法的钛连续冶炼法是当今世界海绵钛生产厂家都在研究开发的新技术,意大利开发的电解法已投入批量生产。     

镁及镁合金熔炼用铁质坩埚腐蚀及防护

镁及镁合金熔炼用铁质坩埚在高温下易氧化腐蚀，严重影响坩埚的使用寿命和合金的质量。本文对熔镁铁质坩埚的腐蚀机理进行了分析，介绍了用复合型坩埚、调整坩埚基体化学成分、表面处理等提高铁质坩埚抗腐蚀能力、延长坩埚使用寿命的方法，并对不同方法存在的问题和解决途径进行了分析。     

铸态珠光体球铁生产中的若干问题

讨论了生产铸态珠光体球铁几个工艺参数的影响。证实：Ｃｕ合金化有较好的综合机械性能：Ｓｂ，Ｃｒ合金化成本较低，也能保证机械强度；Ｓｂ以孕育方式使用有较大优越性，铸态球光体球铁生产应用较低硅量，对缩孔没有决定性的影响，粉状ＳｉＣａ用于随流孕育可提高孕育效果。     

碘化钛的电子束熔炼提纯效果分析

通过对碘化钛电子束熔炼提纯效果分析，提出合理、经济的高纯钛制取工艺路线。     

激光熔炼W/W2Ni3Si金属硅化物“原位”复合材料的耐磨性

采用水冷铜模激光合金熔炼炉制备了以初生w树枝晶为增强相、以w2Ni3Si三元金属硅化物为基体的金属硅化物“原位”耐磨复合材料．分别在室温干滑动磨损及600℃高温滑动磨损条件下测试了上述W／W2Ni3Si金属硅化物“原位”增强耐磨复合材料的耐磨性，并讨论了其磨损机理．结果表明，上述金属硅化物耐磨复合材料在室温干滑动磨损和高温滑动磨损条件下均具有优异的耐磨性能．     

Thermodynamic properties and mixing thermodynamic parameters of Ba-Al, Mg-Al, Sr-Al and Cu-Al metallic melts

Application of equations of mixing thermodynamic parameters formulated on the basis of the coexistence theory of metallic melts in Ba-Al, Mg-Al, Sr-Al and Cu-Al melts leads to fruitful results that not only the evaluated mass action concentrations agree well with the measured activities, but also the calculated mixing thermodynamic parameters are quite coincident with the experimental values. Moreover, the calculated mass action concentrations strictly obey the mass action law. The evaluated mixing thermodynamic parameters have very fine regularity: the mixing free energy is composed of standard free formation energies of all compounds and chemical potentials of all structural units at equilibrium; the mixing enthalpy consists of standard formation enthalpies of all compounds; the mixing entropy is composed of standard entropies of all compounds and configuration entropies of all structural units at equilibrium. As the equations of mixing thermodynamic parameters formulated are widely applicable to metallic melts involving compound formation, they can be used as the second practical criterion to determine whether thermodynamic models of metallic melts are correctly formulated.     

真空熔炼AZ91镁合金过程中Mg元素的蒸发行为

在真空Ar气氛中熔炼AZ91镁合金，测定了不同精炼温度下Mg元素的蒸发速率。结果表明，随着精炼温度的升高，Mg元素的蒸发量增大。通过计算可知，Mg的蒸气压是Al的10^9倍，是Zn的46倍，因此主要是Mg的蒸发而导致合金其他元素含量升高。XRD分析表明，蒸发物是Mg元素。结合Mg元素的蒸发机制，在该试验条件下推导出Mg元素蒸发率的计算公式以及Mg元素的表观传质系数、蒸发率与精炼温度的关系，计算得出Mg元素蒸发率为0．86×10^-3-1．35×10^3g／cm^2·s，Mg元素的表观传质系数在2×10^-5-24×10^-5cm／s范围内。     

熔剂熔炼AM60B镁合金中的夹杂物

采用扫描电镜及能谱对AM60B镁合金中夹杂物进行了研究,并就AM60B镁合金铸件中夹杂物的形成原因以及它们对镁合金铸件质量的影响进行了分析。通过大量试验,得到在镁合金中存在的夹杂主要有氧化物夹杂、熔剂夹杂、外来夹杂等几种,其中最主要的是氧化物夹杂。通过适当工艺可以去除大部分夹杂物。     

Induction plasma spheroidization of tungsten and molybdenum powders

The melting, evaporation and oxidation behaviors as well as the solidification phenomena of tungsten and molybdenum in induction plasma were studied. Scanning electron microscopy was used to examine the morphology and the cross section of plasma-processed powders. X-ray diffraction was used to analyze the oxides formed on the particle surface of these two metals. The influence of spray chamber pressure on the spheroidization and oxidation phenomena was discussed. The results show that fewer Mo particles than W particles are spheroidized at the same powder feed rate under the same plasma spray condition although molybdenum has a lower melting point. A small fraction of tungsten is evaporized and condensed either on the surface of tungsten particles nearby or on the wall of spray chamber. Tungsten oxides were found in tungsten powder processed under soft vacuum condition. Extremely large grains form inside some spheroidized particles of tungsten powder.     

冷坩埚熔铸技术的研究及开发现状

综述了冷坩埚技术的原理和特点、目前的研究及开发现状。冷坩埚具有无污染，可熔化高熔点金属，制备的材料组织均匀等优点。冷坩埚技术在以下领域得到广泛的研究和应用：与熔化技术相结合能高纯均匀熔炼活性金属，通过起熔材料能制备陶瓷材料；与连铸技术相结合能进行冷坩埚电磁连铸技术，提高铸锭表面质量，改善内部组织；与定向凝固和连铸技术相结合的冷坩埚定向凝固技术已成功进行钛合金的定向凝固；与多晶硅制备技术相结合能连续制备多晶硅，杂质含量少；与雾化沉积技术相结合的冷坩埚雾化沉积技术具有熔化合金种类多、适用范围广的优点。冷坩埚的自身特点决定了其必将更受重视和广阔发展前景。