金属Zr热力学性质的第一原理研究

应用基于密度泛函与密度泛函微扰理论的平面波赝势方法计算了一组不同晶格常数下hcp结构金属Zr的声子谱及相应的静态总能,由此得到不同晶格常数下的自由能,由准谐近似及自由能极小判据得到自由能与温度的关系,进而计算了金属Zr热膨胀系数、体弹性模量、定容及定压摩尔热容与温度的关系,计算结果在较宽的温度范围内与实验相符.对热膨胀系数,同时应用Debye-Grüneisen模型进行了计算,并与第一原理方法的结果进行了比较.对摩尔热容的计算考虑了电子的贡献,表明在高温区电子热容的贡献不能忽略.     

B2FeAl合金晶格动力学的嵌入原子模型计算

应用改进分析型EAM模型，系统计算了B2FeAl合金的晶格动力学性能，包括晶格常数、形成热、弹性常数、声子谱、态密度、比热、德拜温度和热膨胀系数等，并将计算结果与已有实验数据及其他理论计算结果进行了比较。总的来说，仅从合金组成元素的性质出发，不涉及合金本身性质而构建的改进分析型EAM模型成功地描述了B2FeAl合金原子间的相互作用，所得计算结果与实验值符合很好。     

Al-Pb互不溶体系机械合金化过程中固溶度的计算

计算了 8种fcc金属 (Ag ,Al,Au ,Cu ,Ni,Pb ,Pd和Pt)和Al Pb互不溶体系的嵌入原子势 (EAM) ,并计算了用EAM模型计算的结构稳定性。计算结果和实验结果吻合较好 ,而且拟合得到的fcc模型在结构上是稳定的。运用拟合得到的数据计算了Pb在Al中的溶解热 ,结果与abinitio计算结果相近。根据机械合金化扩展固溶度的理论 ,计算了Al Pb互不溶体系机械合金化后的固溶度 ,约为 0 .19% (摩尔分数 )。     

钯的反演势的构建与研究

以面心立方金属钯为研究对象,基于第一性原理中的局域密度近似理论(LDA),计算了不同晶格长度下的原子间内聚能并得到其原子内聚能曲线.通过陈-莫比乌斯晶格反演势理论,得到了精确的反演对势曲线.采用不同势函数对该曲线拟合,通过对拟合效果的对比和分析,提出了全局精度较高的双指数型势函数.同时,分别采用第一性原理方法,原子嵌入势(EAM)方法和反演势数据计算了钯的声子谱.比较声子谱曲线发现,曲线的变化趋势是相似的,说明反演势可以合理的反应原子间相互作用.并且反演势方法所需的计算时间明显少于EAM势方法,说明反演势方法在计算量上有明显优势.最后,计算了金属钯的热膨胀系数,弹性模量和格林乃森常数等物理量.计算结果与实验数据基本符合,表明构建的钯的反演势是准确有效的.     

钯的反演势的构建与研究（英文）

以面心立方金属钯为研究对象,基于第一性原理中的局域密度近似理论(LDA),计算了不同晶格长度下的原子间内聚能并得到其原子内聚能曲线。通过陈-莫比乌斯晶格反演势理论,得到了精确的反演对势曲线。采用不同势函数对该曲线拟合,通过对拟合效果的对比和分析,提出了全局精度较高的双指数型势函数。同时,分别采用第一性原理方法,原子嵌入势(EAM)方法和反演势数据计算了钯的声子谱。比较声子谱曲线发现,曲线的变化趋势是相似的,说明反演势可以合理的反应原子间相互作用。并且反演势方法所需的计算时间明显少于EAM势方法,说明反演势方法在计算量上有明显优势。最后,计算了金属钯的热膨胀系数,弹性模量和格林乃森常数等物理量。计算结果与实验数据基本符合,表明构建的钯的反演势是准确有效的。     

D03结构Fe3Al合金晶格动力学的嵌入原子模型计算

应用改进分析型嵌入原子模型，系统地计算了D03结构Fe3Al合金的晶格动力学性能，包括晶格常数、形成热、弹性常数、声子谱、态密度、摩尔定容热容、德拜温度和热膨胀系数等，并将计算结果与已有实验数据和其他理论计算结果进行了比较。计算所得声子谱相对于其他理论计算结果而言，与实验值的符合程度更好；计算的热膨胀量在低温区与实验结果基本一致，而在高温区明显偏低于实验结果。     

铂的反演势的构建与研究

通过第一性原理计算得到了铂的晶格内聚曲线,而后利用陈式晶格反演方法,得到了反演势曲线。利用提出的双指数函数,拟合得到了精确的铂原子的反演势函数。利用反演势数据、EAM(嵌入式原子法)势理论和第一原理分别计算声子谱,验证了反演势的可靠性。提出了将玻尔兹曼统计方程与晶格粘聚能曲线精确拟合相结合的热膨胀系数计算方法。此外,还计算了室温下的体积模量和格鲁内森常数。结果与实验结果吻合较好,说明计算得到的铂的反演势是有效的、准确的。     

铂的反演势的构建与研究（英文）

通过第一性原理计算得到了铂的晶格内聚曲线,而后利用陈式晶格反演方法,得到了反演势曲线。利用提出的双指数函数,拟合得到了精确的铂原子的反演势函数。利用反演势数据、EAM(嵌入式原子法)势理论和第一原理分别计算声子谱,验证了反演势的可靠性。提出了将玻尔兹曼统计方程与晶格粘聚能曲线精确拟合相结合的热膨胀系数计算方法。此外,还计算了室温下的体积模量和格鲁内森常数。结果与实验结果吻合较好,说明计算得到的铂的反演势是有效的、准确的。     

First Principles Study of Stability and Thermal Properties of AuxCuy Compounds

采用密度泛函理论研究了AuxCuy金属间化合物的稳定性,热学和力学性能。通过计算AuxCuy各合金相的形成能和生成焓可知各个合金相是热力学稳定的,且计算出来的晶格常数与实验值吻合得较好。采用准简谐近似法计算了合金相的定容比热,对与化学键强度相关的德拜温度也进行了讨论。体模量,杨氏模量等弹性性质用Hill法进行了计算。通过计算声子谱和声子态密度讨论了2种不同结构AuCu合金相的稳定性。研究结果将为Au-Cu系的进一步开发应用提供理论基础。     

Au_xCu_y金属间化合物的稳定性和热学性能的第一性原理研究（英文）

采用密度泛函理论研究了Au_xCu_y金属间化合物的稳定性,热学和力学性能。通过计算Au_xCu_y各合金相的形成能和生成焓可知各个合金相是热力学稳定的,且计算出来的晶格常数与实验值吻合得较好。采用准简谐近似法计算了合金相的定容比热,对与化学键强度相关的德拜温度也进行了讨论。体模量,杨氏模量等弹性性质用Hill法进行了计算。通过计算声子谱和声子态密度讨论了2种不同结构AuCu合金相的稳定性。研究结果将为Au-Cu系的进一步开发应用提供理论基础。     

Direct current testing to measure corrosiveness of wood preservatives

A qualitative test that mimics the corrosion behaviour of metals in contact with treated wood without using wood specimens would be of great value in rapidly evaluating the corrosiveness of new wood preservatives. The objective of this study was to determine whether the linear polarisation resistance of metals immersed in a solution of preservative chemicals is related to corrosion of metals in wood. This technique was used to measure the corrosion rate of four types of metals in three different aqueous solutions of wood preservatives. The four metals were UNS G10180 (SAE 1018 steel), UNS S30400 (AISI 304 stainless steel), UNS S43000 (AISI 430 stainless steel), and UNS Z15001 (zinc). The metals were subjected to various concentrations of alkaline copper quat (ACQ-D), ammoniacal copper citrate (CC), and chromated copper arsenate type C (CCA-C). It was found that the corrosion of metals in the solutions of the wood preservatives did not correlate well to what is known about the corrosion of metals in contact with wood.     

The corrosion behavior of Fe-Mn-Al weld metals

The corrosion resistance of a newly developed iron-base, Fe-Mn-Al austenitic, and duplex weld metal has been examined in the NACE solution consisting of 5 wt.% NaCl, 0.5 wt.% acetic acid, and the balance distilled water. The electrochemical techniques such as potentiodynamic polarization, Tafel plots, linear polarization, cyclic polarization, and open-circuit potential versus time were employed. The Fe-Mn-Al weld metals did not passivate and exhibited high corrosion rates. Fe-Cr-Ni (310 and 316) weld and base metals were also examined in the NACE solution at room temperature. The 310 and 316 base metals were more resistant to corrosion than the as-welded 310 and 316 weld metals. Postweld heat treatment (PWHT) improved the corrosion performance of the Fe-Mn-Al weld metals. The corrosion resistance of Fe-Mn-Al weld metals after PWHT was still inferior to that of the 310 and 316 weld and base metals.     

Effects of Cu, Si, Ni and rare earth elements on melting temperature and properties of Al-Si filler metals

The effects of Cu,Si,Ni and RE elements (RE=La and Ce) on the melting temperature of Al-Si filler metals were studied by orthogonal design method.The wettability of the filler metals and the shear strength of 6063 aluminum alloy joints brazed with the different filler metals were measured.The results show that the copper doping content has the most obvious effect on liquidus temperature (T_L) of the Al-Si filler metals and the effect of RE content on T_L is the least.Adding suitable Cu and Si can improve the wettability of the Al-Si filler metals.The shear strength of 6063 aluminum alloy joints brazed with the filler metals S10,S15 and S20,respectively,is better than that of the joints brazed with HL401 due to the improvement of microstructure.It can improve the shear strength of the joints by brazing with the Ni- or RE-doped Al-Si-Cu filler metals.     

难熔金属热学性能的研究现状

综述了难熔金属（钒、铌、钽、钼、钨等）热学性能的研究现状及其进展,从理论和实验两方面讨论了难熔金属热学性能与微观结构之间的关系.简述了纳米晶难熔金属的研究现状.最后对难熔金属研究与应用的前景进行了展望.     

基于改进的潜在生态风险指数的霞湾港底泥重金属生态风险评价(英文)

基于潜在生态风险指数(RI)和风险评价代码(RAC),建立改进的潜在生态风险指数(MRI)。该方法考虑了单个重金属不同形态毒性的不同。以株洲霞湾港底泥为例,研究Cd、Cu、Pb、Zn的污染状况及其形态特征,并分别运用潜在生态风险指数、风险评价代码以及改进的潜在生态风险指数3种方法对霞湾港底泥进行风险评价。实验数据显示,霞湾港底泥的重金属污染严重。根据改进的潜在生态风险指数,重金属生态风险呈现CdPbCuZn递减的顺序。通过对比得出,改进的生态风险评价综合了潜在生态风险指数和风险评价代码2种方法的优点,评价结果更加可靠,能够为风险管理提供一定的理论依据。     

Corrosion behaviour of 304LN activated tungsten inert gas and flux-cored arc weld metals

Activated tungsten inert gas (A-TIG) and flux-cored arc (FCA) weld metals were prepared using 304LN stainless steel plate. The weld metals were thermally aged at 923, 973 and 1023?K for 100?h to study the decomposition of initial δ-ferrite in A-TIG (～10 ferrite number (FN)) and FCA (～5 FN) weld metals into secondary phases like M₂₃C₆ carbides, χ and σ. Ferrite number is the measurement of δ-ferrite based on the principle of magnetic property using ferritescope. Preliminary microstructural studies revealed the formation of carbides in FCA weld metals aged at 923?K for 100?h, which was correlated with higher carbon content (0.04?wt-%), and also ageing at higher temperature transformed δ-ferrite into χ/σ phases. However, A-TIG weld metals showed the transformation of δ-ferrite mainly into χ/σ phases. The δ-ferrite transformation kinetics was found to be sluggish in A-TIG weld metals compared to FCA weld metals. This difference was attributed to the difference in the carbon contents of A-TIG and FCA welds. Activated tungsten inert gas weld metals showed better uniform and pitting corrosion resistance compared to FCA weld metals in as-deposited and thermally aged conditions. Presence of higher amount of initial δ-ferrite content in A-TIG weld metal helped diffusion of minor alloying elements like sulphur and phosphorous into it, thereby reducing their microsegregation at the δ/γ interface boundaries and subsequent pitting corrosion attack. Thus, A-TIG welding process was found to be superior compared to FCA welding process.     

微米锡刷镀层对AgCuZnSn钎料性能的影响

以BAg34CuZnSn钎料为研究对象,在其表面刷镀微米锡层,利用SEM和XRD表征锡刷镀层的组织和结晶取向,采用差热分析仪(DSC)、润湿试验炉、万能拉伸试验机分析刷镀锡含量对钎料熔化温度、润湿性、抗拉强度的影响,并对刷镀锡后钎料的电阻率和断后伸长率进行了讨论. 结果表明,BAg34CuZnSn钎料表面微米锡刷镀层平整、致密,孔隙率小,结晶晶粒呈现明显的(200),(112)择优取向. 随着钎料表面刷镀锡含量升高,AgCuZnSn钎料的DSC吸热峰向左偏移、熔化温度逐渐降低,钎料润湿面积和断后伸长率呈上升趋势,而钎料的抗拉强度和电阻率逐渐下降. 在刷镀锡含量为2.0%时,钎料的润湿面积和断后伸长率最大,而钎料熔化温度、抗拉强度和电阻率最低.     

Microstructures and properties of low-melting-point Al-Cu-Si filler metals prepared by different technologies

The Al25Cu6. 5Si0. 09RE (RE = La and Ce) and Al25Cu10.5Si2Ni filler metals were prepared by common metal mold casting, copper plate chilling and rapid solidification, respectively. The microstructures and properties of these filler metals were studied. The results show that the as-casting and the corresponding rapid solidification filler metals have the same phases but their microstructures are different. The microstructure of rapid solidification filler metals consults of an a-Al solid solution, the 6 (Al2Cu) intermetallic compound and an Al-Cu-Si eutectk phase. Compared with the as-casting filler metal, the melting temperature ranges (△T) of the corresponding copper plate chilling and rapid solidification filler metals decrease and their wettabilities are improved because of the grain refinement and the improvement of composition uniformity. The wetting area of Al25Cu6.5Si0.09RE rapid solidification filler metal doubles that of the corresponding as-casting filler metal. It is hopeful that the properties of Al-Cu-Si filler metals will be improved by changing preparation technology.     

铜镍合金氯化渣富集贵金属

针对含贵金属０．１２％的高冰镍磨浮磁选铜合金氯化浸出渣富集贵金属生产流程中的不足,提出了新的工艺流程结构,包括煤油脱除元素硫－熔炼含贵金属高锍－加压酸浸三个步骤,贱金属分离效率（％）：Ｃｕ９９．５、Ｎｉ９９．８、Ｆｅ９４．５、Ｓ９９．６、ＳｉＯ２９８．８;贵金属回收率（％）：Ｐｔ９８．０、Ｐｄ９７．０、Ａｕ９７．０,产出贵金属品位〉３０％,贵贱比〉１的精矿。     

温度对六方系金属层错能影响的热力学模型

利用密排六方金属发生层错时在层错区域由密排六方(Hexagonal Close-packed,hcp)的AB排列转变为面心立方(Face-centered Cubic,fcc)的ABC排列的特点,通过计算hcp/fcc相变所需要的能量来计算hcp金属层错能.同时,在模型中引入了空位缺陷和温度等因素.利用此模型计算Mg,Zn,Ti等3种hcp纯金属的层错能,推导出层错能随温度变化的理论计算式,计算出变化值.计算结果表明:该热力学模型适用于hcp金属层错能的计算.Mg,Zn,Ti等hcp结构金属的层错能随着温度的升高逐渐降低,化学自由能变对层错能的影响占主导地位.空位有降低层错能的作用,随着温度的升高空位密度增大,层错能降低的幅度增大.