ICP-AES法测定镍基、铁镍基高温合金与结构钢中的微量硼

本文采用ＩＣＰ－ＡＥＳ法对镍基、铁镍基高温合金与结构中微量硼元素的测定进行了研究,着重考察了镍基ＤＺ１２５合金,铁镍基ＧＨ４１６９合金和结构钢的基体与合金元素对硼含量测定的影响,采用了分步沉淀分离方法,消除了铁（基体）、钨和铌,钽（合金中共存元素）对硼的干扰,测定了样品中微量硼,取得了满意的结果。     

ICP-AES法分析Au-Be合金

研究了用ＩＣＰ－ＡＥＳ法测定Ａｕ－Ｂｅ合金中Ｂｅ及萃取Ａｕ后测定微量Ｐｔ、Ｐｄ、Ｒｈ、Ｉｒ、Ａｇ等２５个杂质元素的方法。元素间的干扰用等效浓度法校正。杂质元素标准加入回收率为９６－１０７％,相对标准偏差为１．７－１２％。取２．５ｇ试样时相对分析下限为１×１０＾－４－５×１０＾４％。测定合金成分Ｂｅ时相对误差不大于２％。     

绝对量内标控制ICP－AES法同时测定合金中的多元组分

本文采取在标样和试样中加入绝对量一致的内标元素控制的ＩＣＰ－ＡＥＳ法，对合金中的多元组分进行同时测定。通过对Ａｇ－Ｍｇ－Ｎｉ合金中Ｍｇ、Ｎｉ的分析研究和试样测定，获得较好的准确度、精密度，相对误差Ｍｇ＜±０．５％，Ｎｉ＜±３．０％，相对标准偏差均小于０．５％，能满足对合金分析的要求。适当调整称样量及待测溶液定容体积，可扩大测定范围。采用绝对量内标控制，大大减小了由称量和稀释溶液体积带入的误差，从而提高了分析的准确度和精密度     

Al元素含量对高熵合金Al_xFeTiCrZnCu力学性能的影响

采用第一性原理密度泛函理论，结合平面波赝势和广义梯度近似(GGA)，用虚拟晶体近似(VCA)的方法建立高熵合金的固溶结构模型，计算了高熵合金Al_xFeTiCrZnCu的结构性能、弹性性能和生成热.计算结果表明，Al_xFeTiCrZnCu高熵合金的密度随着Al元素含量的增加而减小，晶格常数在Al元素摩尔含量为1时最小.Al元素含量的增加能提高高熵合金Al_xFeTiCrZnCu的力学稳定性.基态总能量和生成热都随着Al元素含量的增加而增加，但是合金系的稳定性和热力学稳定性有所下降.     

基于LIBS技术的钢铁合金中元素多变量定量分析方法研究

针对钢铁合金样品元素组成相对复杂,基体效应较严重的问题,利用激光诱导击穿(LIBS)光谱技术对钢铁合金中的元素进行了定量分析。以Nd∶YAG脉冲激光器基频1 064 nm波长激光作为激发光源,采用中阶梯光栅光谱仪和ICCD分光探测钢铁合金样品的LIBS光谱。通过优化实验确定最佳探测延时为1.5 μs,最佳探测门宽为2 μs,激光聚焦点位置在实验样品靶面以下1.5 mm。采用单变量定量分析、多变量线性回归和偏最小二乘(PLS)三种方法分析钢铁合金中Cr元素和Ni元素的含量。结果表明,采用单变量定标方法定标曲线相关系数不高,对待测样的预测误差相对较大,难以有效地定量分析基体元素复杂的钢铁合金中金属元素的含量;采用多变量线性回归分析方法能有效提高定量分析的精度;采用PLS方法得到的Cr和Ni元素的拟合曲线相关系数r分别为0.981和0.995,对两个待测样品中Cr元素和Ni元素的预测相对误差在6.4%和7.1%以内,分析结果优于多变量线性回归方法。可见,采用多变量校正的PLS方法能更有效地校正基体效应对定量分析的影响,提高定量分析的精度。     

Bi，Sb合金化对AZ91镁合金组织、性能影响机理研究

利用大角重位点阵模型建立了AZ91镁合金α相［0001］对称倾斜晶界原子结构模型，应用实空间的连分数方法计算了Mg合金的总结构能，合金元素引起的环境敏感镶嵌能及原子间相互作用能，讨论了主要合金元素Al及Bi，Sb在AZ91中的合金化行为.计算结果表明，Al，Bi，Sb固溶于α相内或晶界区使总结构能都降低，起到固溶强化作用；合金元素在AZ91α相内趋于均匀分布，在晶界区易占位于三角椎上部.AZ91镁合金中加入Bi或Sb时，Bi或Sb比Al容易偏聚于晶界，从而抑制了Al在晶界的偏聚，促进基体中连续的Mg₁₇Al₁₂相的析出，提高AZ91合金室温性能； AZ91合金中(α相内和晶界区)主要合金元素Al和微加元素Bi，Sb都能够形成有序相Mg₁₇Al₁₂，Mg₃Bi₂或Mg₃Sb₂，且在晶界区形成的量大.Bi，Sb加入AZ91合金中，由于Bi，Sb抑制Al在晶界的偏聚，晶界区主要析出相为Mg₃Bi₂或Mg₃Sb₂，提高镁合金高温性能. 关键词： 电子理论 合金化 晶界偏聚 镁合组织与性能     

微合金化元素晶界偏聚与钢的超细化理论研究

通过计算机编程建立钢奥氏体相中Σ5〈001〉/(210)大角晶界模型，用实空间的递推方法计 算碳、氮及微合金元素在完整晶体及晶界区引起的环境敏感镶嵌能，进而讨论碳、氮及微合 金元素在晶界区的偏聚及交互作用.计算结果表明，轻杂质C，N易偏聚于晶界区，且形成气 团；微合金元素在完整的奥氏体中趋于均匀分布，Ti，V，Nb易占位于晶界三角棱柱的顶部( 压缩区)，且其加入量足够大时，它们能够在晶界区形成气团；微合金元素能够偏聚于C，N 掺杂的大角晶界区，当温度下降使得C，N及微合金元素的浓度超过其最大固溶度时，在钢的 奥氏体晶界区将有C，N化合物脱溶，这些化合物既可成为奥氏体再结晶的异质晶核，又可以 阻碍奥氏体晶粒长大，故可起到细化晶粒作用.在微合金元素中Nb的细化效果最好. 关键词： 电子结构 晶界偏聚 超细化     

电负性与超导电性

通过对合金类和氧化物类以及其它化合物超导体的电负性的平均效应进行研究，发现它们具有很好的规律性。如合金类超导体的电负性平均效应值χ介于１．５至１．９之间；氧化物超导体中各正价元素电负性的平均效应的η值介于１．３至１．６之间；负价元素（氧）的总体平均效应ξ值介于１．７５至２．００之间，而这两的平均值χ介于１．５至１．８之间，当η和ξ都处于极限值（１．３或１．６和１．７５或２．００）附近时，Ｔｃ较低     

钢铁材料组织超细化机理的电子理论研究

通过计算机编程建立奥氏体相中的1/2［110］刃位错，用实空间的递推方法计算碳、氮及合金元素在完整晶体及位错区引起的环境敏感镶嵌能，进而讨论碳、氮及合金元素在位错区的 偏聚及交互作用.计算结果表明：分立的轻杂质C，N易偏聚在位错区，它们在刃位错上方形 成柯氏气团；合金元素在完整的奥氏体晶体中趋于均匀分布，强、中碳化物形成元素（Ti, V, Nb, Cr）易在刃位错区偏聚，它们在位错上方形成柯氏气团，而非碳化物形成元素Ni偏 聚于位错线下方，或分布于非缺陷区；轻杂质加剧强碳化物形成元素在刃位错区的偏聚.当 温度下降使得C，N及合金元素的浓度超过其最大固溶度时，在钢的奥氏体刃位错区将有C，N化合物脱溶，这些化合物可作为奥氏体再结晶的异质晶核，细化晶粒. 关键词： 电子结构 位错 超细化     

用DV－4光谱仪分析航空结构钢中Pb、Sn、As、Sb、Bi

本文介绍了分析航空结构钢中Ｐｂ、Ｓｎ、Ａｓ、Ｓｂ、Ｂｉ残余元素的一种新的快速方法──发射光谱分析法，找出了最佳分析参数，建立了校准曲线，经精密度和准确度试验后，相对标准偏差为１．２５％－９．１０％，结果令人满意。     

采用激光诱导击穿光谱技术测定合金钢中锰和硅的含量

基于激光诱导击穿光谱(LIBS)技术定量分析多品种合金钢中锰(Mn)和硅(Si)的浓度,采用的校正方法为多元二次非线性函数定标方法。分析的钢种有普通合金钢、不锈钢、碳素工具钢等。由于不同钢种在基体组成上存在较大差异,而且钢的光谱还存在复杂的谱线重叠干扰,所以受基体效应影响严重。因此,对钢这类复杂化学体系物质的定量分析,若采用单谱线信息的校正方法会造成很多有用信息的丢失,而采用多变量的定标法会更充分利用光谱中的信息,更有效校正多基体组分的基体效应,进而提高LIBS定量分析的重复性和准确性。相比线性标准定标曲线法,测量结果的相对标准差从20%以上降低到10%以下,Mn元素测量结果的准确度提高了5倍多,Si元素提高了6倍多。     

Quantitative analysis of Mn and Si of alloy steels by laser-induced breakdown spectroscopy

The concentration of Mn and Si in different kinds of steels was determined by laser-induced breakdown spectroscopy (LIBS). The multivariate quadratic nonlinear function was adopted for calibration. Samples including common alloy steels, stainless steels and carbon tool steels were analyzed. The matrix effect was serious because of large difference in compositions of different kinds of steels and strong line overlaps in steel spectra. Therefore, the common calibration methods that only use one analytical line to calibrate the complex chemical compositions of alloy steels will lose much information. The multivariate calibration methods, however, can utilize more information of spectra, successfully reduce the matrix effect and improve the measurement repeatability and accuracy of LIBS. Compared with the common calibration method based on one analytical line, the relative standard deviation was reduced from above 20% to below 10%, and the accuracy was increased by more than 5 times for Mn and more than 6 times for Si.     

高合金钢光谱分析准确度改进试验

在我国钢铁厂中,高合金钢的光谱分析受到准确度的限制,没有普遍展开。通过对两种有代表性的高合金钢,即P18高速钢及Я1不锈钢的试验,证明用摄谱方法采取种种改进以后,高合金钢的分析约可达到最小的百分均方误差1％左右。文中对某些工厂的先进经验曾加以介绍。对于高合金钢的准确度问题曾予讨论。     

Properties of Goethite Grown under the Presence of Cr3+, Cu2+ and Mn2+ Ions

Hyperfine Interactions - This study is focused on properties of goethite related to the inhibition of the corrosion process in low alloy, weathering steels. These steels are characterized by the...     

碳化物弥散强化钢力学性能及微观组织研究

用碳化物粒子对低活化钢CLF-1进行弥散强化.结果表明机械合金化的方法可以制备高强度的碳化物弥散强化钢,经过60h球磨可完成合金化过程,同时添加的碳化物粒子很好地提高了低活化钢CLF-1的拉伸性能,得到了比熔炼低活化钢更高的强度和硬度,同时保持了较好的延伸率.     

Computational design of precipitation strengthened austenitic heat-resistant steels

A new genetic alloy design approach based on thermodynamic and kinetic principles is presented to calculate the optimal composition of MX carbonitrides precipitation strengthened austenitic heat-resistant steels. Taking the coarsening of the MX carbonitrides as the process controlling the life time for steels in high temperature use, the high temperature strength is calculated as a function of steel chemistry, service temperature and time. New steel compositions for different service conditions are found yielding optimal combinations of strength and stability of the strengthening precipitation for specific applications such as fire-resistant steels (short-time property guarantee) and creep-resistant steels (long-time property guarantee). Using the same modelling approach, the high temperature strength and lifetime of existing commercial austenitic creep-resistant steels were also calculated and a good qualitative agreement with reported experimental results was obtained. According to the evaluation parameter employed, the newly defined steel compositions may have higher and more stable precipitation strengthening factors than existing high-temperature precipitate-strengthened austenite steels.     

Laser ablation of alloys: Selective evaporation model

A mechanism of non-stoichiometric laser ablation is proposed and experimentally verified for multicomponent alloys. The analysis of four-component bronze samples in various excitation modes and the recorded laser plasma spectra revealed that disproportion of plasma elements during laser evaporation arises from selective evaporation of components at the heating-melting-evaporation stage. Correction coefficients proportional to the work function of the alloy component vapor in the heating-melting-evaporation cycle are calculated for the plasma spectrum. Correction procedure for the spectral lines leads to a good agreement of the measured sample composition with the tabulated data. To check that the proposed approach is universal, aluminum alloys and iron alloys (high-alloy stainless steels) are analyzed. It is found that selective evaporation for aluminum alloys is lower than for bronzes. Evaporation selectivity was insignificant for stainless steels. The proposed mechanism for selective evaporation during laser ablation and correction of the plasma spectrum make it unnecessary to use a standard in the quantitative elemental analysis of complex bronze and aluminum alloy samples.     

Non-equilibrium grain boundary cosegregation of Mo and P

The segregation of P at grain boundaries is believed to be an important cause of temper embrittlement in steels. As an alloy element, Mo may reduce the embrittlement. However, the concentration measured by Auger electron spectroscopy at the grain boundary in 2.25Cr1MoV and 12Cr1MoV showed that the concentration of P increased with that of Mo, which indicates that Mo and P cosegregated to the grain boundary in Cr-Mo steels.     

Genetic alloy design based on thermodynamics and kinetics

A theory-guided computational approach for alloy design is presented. Aimed at optimising the desired properties, the microstructure is designed and an alloy composition optimised accordingly, combining criteria based on thermodynamic, thermokinetic and mechanical principles. A genetic algorithm is employed as the optimisation scheme. The approach is applied to the design of ultra-high strength stainless steels. Three composition scenarios, utilising different strengthening precipitates (carbides, Cu and NiAl/Ni₃Ti), are followed. The results are compared to a variety of existing commercial high-end engineering steels, showing that the design strategy presented here may lead to significant improvements in strength beyond current levels.