Al-Si共晶合金微粉熔化的研究

Al-Si共晶合金微粉宜采用坩埚式中频感应加热炉熔化.Al-Si共晶合金熔化时的熔化熵为16.05 J/mol.K,其体积变化与组元间合金元素Al-Si的体积变化不具有加和性.微粉压成块、炉內留有起熔体以及快速升温均有助于提高微粉熔化后的合金回收率.Al-Si共晶合金微粉在大气气氛下经熔化后凝固的合金,其氧含量升高、Si含量降低.     

交流电场对Al-Si共晶合金凝固组织的影响

研究交流电场作用下Al-Si共晶凝固组织的变化。结果表明,电场作用改变了共晶Si的生长形态,随电流密度增加,共晶Si的形态经历一次先细化后粗化的过程。电场的处理作用使Al-Si共晶合金中潜在的形核质点增加,电流密度为16.98mA/mm2时,形核率达到最大值,电场对共晶Si的生长有抑制作用。     

气雾化制备Al-Si钎料粉末的研究

针对铝/不锈钢大面积钎焊对钎料的特殊要求,采用气雾化法制备了Al-Si共晶合金钎料粉末,并对雾化金属熔体质量流率、雾化气体压力及雾化温度等影响雾化效果的主要因素进行了研究.结果表明,在金属液流直径dt=5 mm,雾化气体压力P=1.0 MPa,雾化温度720～770℃的条件下,可制备出75～350μm粉末的质量分数达90%以上的钎料,其各项性能指标均达到法国同类产品的水平.     

气雾化制备Al-Si钎料粉末的研究

针对铝/不锈钢大面积钎焊对钎料的特殊要求,采用气雾化法制备了Al-Si共晶合金钎料粉末,并对雾化金属熔体质量流率、雾化气体压力及雾化温度等影响雾化效果的主要因素进行了研究.结果表明,在金属液流直径dt=5 mm,雾化气体压力P=1.0 MPa,雾化温度720～770℃的条件下,可制备出75～350μm粉末的质量分数达90%以上的钎料,其各项性能指标均达到法国同类产品的水平.     

镁含量对过共晶铝硅合金自生复合Mg2Si组织形貌的影响

采用ZEISS Axioskop2光学显微镜对过共晶Al-Si合金自生Mg2Si增强相组织形貌进行了分析.结果表明,Mg含量为10%时,Mg2Si增强相的组织形貌多为不规则大尺寸的块状;Mg含量为8%时,Mg2Si增强相初生Mg2Si的生成量有些减少,并由不规则大尺寸的块状向汉字状或纤维状开始转变;Mg含量为6%时,其组织形貌呈较完整网络状组织,共晶Mg2Si组织形貌有的呈完整发达的汉字状、树枝状.     

熔体过热处理及冷却速度对Al-Si过共晶合金凝固组织的影响

通过阶梯铸型、定量金相，电子显微技术，研究熔体过热处理、冷却速度对Al-Si过共晶合金铸件组织中初生硅相的影响。结果表明，熔体过热处理可以有效地改善初生硅的大小和分布。过热温度越高，初生硅粒子越细小，分布越弥散。快冷有利于抑制初生硅的析出，而慢冷有利于粗大组织的恢复，但是随着过热温度的升高，初生硅对冷速的敏感性降低。     

过共晶Mg-Cu合金凝固组织中α相的形成机制研究

对Mg-38%Cu过共晶合金的凝固组织研究表明：Mg-38%Cu过共晶合金凝固组织由两种初生相（α、β相）和（α β） 共晶组成;少量的初生β相、α相分布在共晶基体上。Mg-38%Cu过共晶合金中形成亚共晶组织中的初生α相,是非平衡凝固过程中枝晶α相和共晶相之间竞争生长的结果。α相是一种非平衡凝固过程的典型产物, （α β） 共晶是偏离了平衡共晶成分的伪共晶组织,随着冷却速率的增加,β相的尺寸减小,形貌没有发生本质的变化,而α数量有所增加。     

FeNi合金微粉的改性及其电磁与吸波性能

以FeNi_(25)和FeNi_(30)合金微粉作为吸波材料的吸收剂。采用湿磨和退火工艺对合金微粉进行改性,借助X射线衍射(XRD)和扫描电子显微镜(SEM)手段分析了湿磨和退火处理后吸收剂的相组成与微观形貌。采用矢量网络分析仪研究了湿磨和退火处理对合金微粉/硅橡胶复合吸波材料的介电常数、磁导率和吸波性能的影响。结果表明,湿磨15 h后,可成功将球形合金微粉加工成片状,合金中出现α-bcc结构,FeNi合金吸波材料的介电常数与磁导率均得到明显提升。片状FeiNi合金经退火处理后,合金中的α-bcc结构消失,磁导率下降,介电常数略微提高。退火处理改善了FeNi合金吸波材料的吸波性能。     

Al-Ce-P中间合金对ZL102铝硅合金的变质研究

以Ce和P为主要合金元素.采用熔配法制备新型的Al-Ce-P中间合金,用该合金对ZL102铝硅合金进行变质处理,分析其变质效果和工艺参数对变质效果的影响.结果表明,Al-Ce-P中间合金能明显改变铝硅合金中硅相的形态,共晶硅由粗大的长针片状变成了细小的纤维状,初晶硅由板块状变为了均匀的团状,且晶粒尺寸明显减小.当Al-Ce-P中间合金中P含量为4%,变质温度为1003K时,变质效果最佳.     

Al-Ce-P中问合金对ZL102铝硅合金的变质研究

以Ce和P为主要合金元素，采用熔配法制备新型的Al-Ce-P中间合金，用该合金对ZL102铝硅合金进行变质处理，分析其变质效果和工艺参数对变质效果的影响。结果表明。Al-Ce-P中间合金能明显改变铝硅合金中硅相的形态，共晶硅由粗大的长针片状变成了细小的纤维状，初晶硅由板块状变为了均匀的团状，且晶粒尺寸明显减小。当Al-Ce-P中间合金中P含量为4％，变质温度为1003K时，变质效果最佳。     

空气流雾化铝硅共晶合金粉末钎料的粒度分布

对空气雾化制备的Al-Si共晶合金粉末钎料粒度分布进行了研究,结果表明,粉末钎料粒度分布呈双峰曲线,主要分布在105～246 μm之间.运用二次破碎机理对颗粒分布特征进行了分析,并推导出液滴发生二次破碎极限尺寸的计算公式.     

低共熔溶剂中电解分离高铅锑合金制备高纯锑粉

提出了一种在氯化胆碱—乙二醇低共熔溶剂(ChCl-EG DES)中电解分离高铅锑合金制备高纯锑粉的新方法.测试了343 K下SbCl3浓度对SbCl3+ChCl-EG DES的黏度和电导率的影响.发现随着SbCl3浓度的升高,SbCl3+ChCl-EG DES的黏度逐渐增大,电导率反之.采用线性扫描伏安法研究了金属锑和...     

金属相变储热材料铝硅合金储热特性研究

在不同热循环次数下,对含硅质量分数分别为13%,17%和21%的铝硅合金的热物理性能的变化进行了研究,并对基于铝硅合金(13%Si)的太阳能高温热利用系统中储热体的储、放热过程进行了数值模拟.结果表明:随热循环次数的增加,Al-Si合金的熔化潜热、熔化温度、热导率及线膨胀系数等热物性虽然均有不同程度的变化,但所变化的幅度均较小,说明铝硅合金的热物性较为稳定,衰减较慢;储热体在储、放热过程中温度变化平稳,所需集热温度不超过980K,供热温度可达600K以上.     

Temperature dependence of the liquid eutectic lead-lithium alloy density

Lead-lithium alloys are of great interest for practice as the advanced materials to be used in new technique, nuclear energetics, and so forth. Terefore, study on the physico-chemical properties of the latter is of major significance. An analysis of the available literature shows that there are a few works, devoted to study of Pb-Li alloys densities. However, temperature dependence of the density ρ(T), and its temperature coefficientK=dρ/dT for eutectic alloy were obtained by either extrapolation of the density data up to the eutectic alloy''s composition, or calculation method. There is a certain discrepancy amounting to as high as 4,, while the allowable error in the density measurements is less than 0.5,. The discrepancy between the results for the temperature coefficients of density amounts to 80,.In this work we present the experimental data on the temperature dependence of Ph0.83 Li0.17 eutectic alloy''s density in the temperature range 520K to 643 K. The alloys were prepared using Pb and Li with 99. 999, and 99.8, contents of the basic elements, respectively. We use the improved device, which permits to get the results with error less than 0. 15,. The results of 115 measurements of density in 520K to 643K temperature range were processed by the least-square method. Density polytherm of Pb0.83 Li0. 17 eutectic alloy is described by linear equation ρ(T) =9507.89-0. 79813(T-508) , kg/m3 ,where T is the absolute temperature by K. Mearsurement error was 0. 12, at 95, reliability.Discrepancy in the temperature coefficient data was 1.08,.Thus, the temperature dependence of the Pb-Li eutectic alloy density was studied by the precise two-capillary method. The obtained results may be recommended as the most reliable reference data.     

Temperature dependence of the liquid eutectic lead-lithium alloy density

Lead-lithium alloys are of great interest for practice as the advanced materials to be used in new technique, nuclear energetics, and so forth. Terefore, study on the physico-chemical properties of the latter is of major significance. An analysis of the available literature shows that there are a few works, devoted to study of Pb-Li alloys densities. However, temperature dependence of the density ρ(T), and its temperature coefficientK=dρ/dT for eutectic alloy were obtained by either extrapolation of the density data up to the eutectic alloy‘s composition, or calculation method. There is a certain discrepancy amounting to as high as 4%, while the allowable error in the density measurements is less than 0.5%. The discrepancy between the results for the temperature coefficients of density amounts to 80%.In this work we present the experimental data on the temperature dependence of Ph0.83 Li0.17 eutectic alloy‘s density in the temperature range 520K to 643 K. The alloys were prepared using Pb and Li with 99. 999% and 99.8% contents of the basic elements, respectively. We use the improved device, which permits to get the results with error less than 0. 15%. The results of 115 measurements of density in 520K to 643K temperature range were processed by the least-square method. Density polytherm of Pb0.83 Li0. 17 eutectic alloy is described by linear equation ρ(T) =9507.89-0. 79813(T-508) , kg/m3 ,where T is the absolute temperature by K. Mearsurement error was 0. 12% at 95% reliability.Discrepancy in the temperature coefficient data was 1.08%.Thus, the temperature dependence of the Pb-Li eutectic alloy density was studied by the precise two-capillary method. The obtained results may be recommended as the most reliable reference data.     

铝硅合金中铁相存在的形态及影响其形成的因素

铁是铝硅合金中最为常见的杂质，通常以β-铁相存在，对合金的力学性能有很大影响．降低铝硅合金中的铁含量，或使铁以α-铁相形式存在，可消除铁的有害影响．目前，减少β-铁相的方法主要有：加入锰、钴、铍等中和元素；熔体过热法；提高冷却速率等．要消除或减少铁在铝硅合金中的有害影响，必须综合考虑施用各种方法．     

低共熔溶剂中电解分离铜镍合金的研究

摘要：本研究以氯化胆碱-乙二醇低共熔溶剂（ChCl-EG DES）为电解液,铜镍合金和钛片分别作为阳极和阴极,在90℃下对铜镍合金进行了电解分离并在阴极获得了高纯铜粉。系统研究了温度和CuCl浓度对CuCl-ChCl-EG DES黏度和电导率的影响。实验结果表明,CuCl-ChCl-EG的黏度随着温度的升高而减小,随着CuCl浓度的升高而增大。温度和CuCl浓度的升高都会增大溶液的电导率。通过电解实验的研究发现,当CuCl浓度增大,电流效率先增大后减小,电能单耗则相反。当CuCl浓度为2 mol·L-1时,得到的实验结果最佳,此时,电流效率和电能单耗分别为99.23%和498.50 kW·h·t-1。电解分离能够获得粒径约为50 μm ~ 150 μm的不规则的块状铜粉,其纯度高达99.97%。     

铝硅合金中铁相存在的形态及影响其形成的因素

铁是铝硅合金中最为常见的杂质,通常以β-铁相存在,对合金的力学性能有很大影响.降低铝硅合金中的铁含量,或使铁以α-铁相形式存在,可消除铁的有害影响.目前,减少β-铁相的方法主要有:加入锰、钴、铍等中和元素;熔体过热法;提高冷却速率等.要消除或减少铁在铝硅合金中的有害影响,必须综合考虑施用各种方法.