镁合金与钛合金的瞬间液相扩散焊

为实现镁合金AZ31B与钛合金Ti6A14V的可靠连接，研究了两者以Al为中间层的瞬间液相扩散焊接头的微观结构与连接强度。研究结果表明：当焊接时间为180min时，焊接温度是影响界面反应热力学与动力学的主要参数，其对接头的微观组织、接头界面新生相构成与连接强度有重要影响。保温温度低于450℃时，AZ3IB／AI界面无液相产生，无法实现AZ31B与Ti6A14V的可靠连接；保温温度在450℃～480℃变化时，温度对AZ31B／Al／Ti6A14V界面反应的动力学因素有明显影响，且直接决定了焊后接头新生相的构成与分布。470℃保温180min的接头剪切强度较高（72．4MPa），达到AZ31B母材（86MPa）的84．2％。     

快速凝固Mg94.6Zn4.8Y0.6镁合金薄带的组织与性能

采用单辊快速凝固技术制备了Mg94.6Zn4.8Y0.6合金薄带,研究了薄带的组织及性能特征。结果表明:Mg94.6Zn4.8Y0.6镁合金快速凝固薄带组织由过饱和的单相-αMg固溶体组成,沿厚度方向分为两个晶区:近辊面粗大等轴晶区和自由面细小等轴晶区。Mg94.6Zn4.8Y0.6合金快速凝固薄带的显微硬度为85.95HV,在250℃左右保温2 h的显微硬度最高,超过该温度(250~300℃)显微硬度显著下降。     

Effect of temperature on mechanical behavior of AZ31 magnesium alloy

Strain rate sensitivity and tension/compression asymmetry of AZ31 magnesium alloy at different temperatures and strainrates were investigated.Both of mechanical behaviors are temperature dependent.Strain rate sensitivity increases with increasingtemperature.Thermally activated slip is the source of strain rate sensitivity.At the temperature below or near 373 K,strain ratesensitivity is very little.Tension/compression asymmetry in yielding decreases with increasing temperature.Twinning is the reasonof tension/compression asymmetry.At the temperature above or near 573 K,the material shows little tension/compressionasymmetry of the flow stress.     

Wear resistance of ceramic coating on AZ91 magnesium alloy by micro-arc oxidation

The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation （MAO） was characterized. The results show that the ceramic coating （3.4-23 μm in thickness）on the surface ofAZ91 alloy was attained under different micro-arc oxidation treatment conditions, which consist mainly of MgO, Mg2SiO4 and MgSiO3 phases. Nano-hardness in a cross-sectional specimen was determined by nano-indentation experiment. The MAO coatings exhibit higher hardness than the substrate. Dry sliding wear tests for the MAO coatings and AZ91 alloy were also carded out using an oscillating friction and wear tester in a ball-on-disc contact configuration. The wear resistance of the MAO coatings is improved respectively under different treatment time as a result of different structures of ceramic coatings formed on AZ91 alloy.     

粉末冶金法制备SiC晶须增强MB15镁基复合材料

采用粉末冶金法制备了SiC晶须增强镁基复合材料(SiCW／MB15)试样。通过检测基体显微硬度探讨了SiCW对镁合金时效规律的影响，并借助扫描电镜(SEM)、透射电镜(TEM)和拉伸试验，研究了混粉方式对复合材料室温力学性能、SiCW分布及显微结构的影响。结果表明，MB15及其复合材料的时效硬化曲线上均存在双峰现象；SiCW的加入既提高了MB5的硬度，又加快了其时效速度：混粉方式对晶须分布及SiCW／MB15复合材料的室温力学性能影响很大。     

薄带连铸技术的发展现状与思考

综述了钢的薄带连铸及铝合金的薄带铸轧发展现状,简要介绍了在高速钢、硅钢和镁合金的薄带连铸实验研究方面取得的进展.认为钢的薄带连铸技术近年取得了重要突破,未来10年薄带连铸技术可能快速发展;发展特殊性能或难加工合金的薄带连铸可充分发挥快速凝固的优势;采用立式双辊法可望进一步提高铝合金的浇铸速度,特别是高牌号铝合金的浇铸速度;应积极发展镁合金的薄带连铸技术,以改善镁合金板材的塑性加工及耐腐蚀问题.     

复合合金化对AZ91镁合金铸态组织的影响

利用光学显微镜、扫描电镜和X射线衍射仪研究了0.5?、0.2?、0.2%Sr(质量分数,下同)复合合金化对AZ91合金铸态组织影响。结果表明,0.5?、0.2?、0.2%Sr复合加入可以显著细化合金的铸态组织,0.5?、0.2?、0.2%Sr同时加入,其细化效果优于0.5?和0.2?或0.5?和0.2%Sr的复合加入,并且在组织中出现针状或杆状的Al4Ce新相。     

Study on the anodic film formation process of AZ91D magnesium alloy

The formation of anodic film of AZ91D magnesium alloy has been investigated by means of electrochemical impedance spectroscopy (EIS), cyclic voltammetry, anodic polarization curve, current-time transients and SEM technique. The results show that, under our experimental conditions, the formation of AZ91D anodic film follows the mechanism of 3D nucleation with diffusion controlled growth. With the increase of applied anodizing potential, the nucleation type of anodic film changes from progressive to instantaneous. The results also show that the initially formed anodized film is threadlike and porous, and high potential is essential for the formation of good anodic film with excellent properties.     

镁渣膨胀性机理试验研究

通过镁渣形成过程、组成、粉化、颗粒分析和安定性试验,研究了镁渣产生体积膨胀性和膨胀滞后性的机理,提出了减轻或消除其膨胀性和膨胀滞后性危害的方法和措施,为镁渣在建筑、交通、水利等工程领域中的应用提供理论依据和指导。     

关于生产精制元明粉的探讨

介绍了以山西运城南风自产芒硝为原料生产精制元明粉的几种工艺,以及国内外精制元明粉的市场及生产状况.精制工艺包括化学除杂法、原料优选法、重结晶法.结果表明,精制元明粉的生产过程实质是一个除杂、提纯过程：对于钙离子含量高的原料,可采用化学除杂法;对于氯离子含量高的原料,可采用氯离子富集法、冷冻法或洗涤法;镁离子较难去除,可采用水硝洗涤、冷冻法.