应用量子化学研究Ca2Fe2—xAl2O5的水化活性

用量子化学ＳＣＣ－ＤＶ－Ｘα方法分析了Ｃａ２Ｆｅ２－ｘＡｌｘＯ５体系听ａ２Ｆｅ２Ｏ５，Ｃａ２Ｆ３１．４３Ａｌ０．５７Ｏ５和Ｃａ２Ｆ３１．２８Ａｌ０．７２Ｏ５，认为它们的水化活性随Ａｌ的增加而提高的原因是：（１）Ａｌ的净电荷比Ｆｅ高，易吸收水分子的弧对电子；（２）Ａｌ－Ｏ键比Ｆｅ－Ｏ键弱，易断裂而容易与水反应。     

Fe—40Al及其含Mn或Ti合金的Mossbauer谱

用Ｍｏｓｓｂａｕｅｒ谱研究了Ｂ２结构金属间化合物Ｆｅ－４０Ａｌ及其加Ｍｎ或Ｔｉ量分别为１，５，１０ａｔ．－％的合金．在室温下，Ｆｅ－４０Ａｌ及其合金的Ｍｏｓｓｂａｕｅｒ谱均接近单峰谱线，Ｆｅ原子无明显磁矩对加入第三组元的Ｆｅ—４０Ａｌ合金的Ｍｏｓｓｂａｕｅｒ谱用最小二乘法拟合为两条洛仑兹曲线之和，认为Ｍｎ原子既占据Ｆｅ原子位置，也占据Ａｌ原子位置；而Ｔｉ原子优先占据Ｆｅ原子位置，超过５ａｔ．－％时，才有少量Ｔｉ原子占据Ａｌ原子位置．     

Fe—40La及其含Mn或Ti合金的Mossbauer谱

用Ｍｏｓｓｂａｕｅｒ谱研究了Ｂ２结构金属间化合物Ｆｅ－４０Ａｌ及其加Ｍｎ或Ｔｉ量分别为１，５，１０ａｔ．－％的合金，在室温下，Ｆｅ－４０Ａｌ及其合金的Ｍｏｓｓｂａｕｅｒ谱均接近单峰谱线，Ｆｅ原子无明显磁矩。对加入第三组元的Ｆｅ－４０Ａｌ合金的Ｍｏｓｓｂａｕｅｒ谱用最小二乘法拟合为两条洛仑兹曲线之和，认为Ｍｎ原子既占据Ｆ原子位置，也占据Ａｌ原子位置；而Ｔｉ原子优先占据了Ｆｅ原子位置，超过５ａｔ．－％     

（Ni,Fe）Al金属间化合物的快速凝固组织与室温塑性

用单辊快速凝固法制备（ＮｉＦｅ）Ａｌ金属间化合物并研究其组织与室温塑性。结果表明，Ａｌ－４５Ｎｉ－５Ｆｅ（原子分散）在快速凝固条件下可形成内部为亚微米级针状亚晶的等轴晶粒，具有高达３．１％的弯曲塑性，Ａｌ－３５Ｎｉ－１５Ｆｅ和Ａｌ－２５Ｎｉ－２５Ｆｅ的快凝组织则为柱状晶，弯曲塑性仅有１．１％１．０％，针状亚晶是一定成分的（Ｎｉ，Ｆｅ）Ａｌ在快速凝固条件下形成的亚稳相，其形成机制和快速凝固过程中原子     

Al-TiO2-C-Ti-Fe体系反应过程研究

采用ＤＳＣ和ＸＲＤ对不同Ｆｅ含量Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－Ｆｅ体系的燃烧反应过程进行了研究。结果表明,Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－Ｆｅ体系的反应是分步进行的。在高温区以金属间化合物的分解及Ｔｉ、Ｃ反应为主;在低温区则随着Ｆｅ含量的不同存在不同的反应：Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ以Ａｌ、Ｔｉ的反应为主,Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－２０ｗｔ％Ｆｅ以Ａｌ、Ｔｉ及Ａｌ、Ｆｅ反应为主,同时还存在Ａｌ、ＴｉＯ２及Ｆｅ、Ｔｉ反应,而Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－５０ｗｔ％Ｆｅ则以Ｆｅ、Ａｌ和Ｆｅ、Ｔｉ反应为主。     

室温应变速率及Al含量对FeAl合金拉伸性能的影响

研究了初始应变速率在１．３９×１０＾４￣６．９５×１０＾－１ｓ＾－１范围内Ｆｅ－４０Ａｌ的室温拉伸性能。结果发现，应变速率对ＦｅＡｌ合金室温下的断裂延伸率屈服强度和抗拉强度均有不同程度的影响，其中对断裂延伸率的影响最为显著。应变速率对ＦｅＡｌ合金力学性能的影响程度还与Ａｌ含量有关，Ｆｅ－３６．５Ａｌ较Ｆｅ－４０Ａｌ合金受应变速率的影响更大，研究结果还表明，Ａｌ含量还影响着ＦｅＡｌ合金拉伸断口中穿晶     

B2型Fe—Al合金键结构及脆性的电子理论研究

应用余氏理论，对不同Ａｌ含量的富Ｆｅ区Ｆｅ－Ａｌ无序固溶体进行价电子结构计算和分析，从理论上探讨了Ａｌ含量对合金晶格常数，原子磁矩，塑性以及晶内原子状态的，研究发现，Ｆｅ－Ａｌ无序固溶体的晶格常数，原子磁矩和塑性随含Ａｌ量的变化，是由于合金中Ｆｅ，Ａｌ原子之间相互作用导致原子状态发生变化的结果。     

快速凝固Al-Fe基合金的组织演化和相选择

对Ａｌ－７．８３Ｆｅ,Ａｌ－５．１６Ｆｅ（ｗｔ％）两种Ａｌ－Ｆｅ快凝条带中不同冷速部位组织进行了ＴＥＭ分析,着重考察了Ａｌ－Ｆｅ快凝合金的组织演化演化及其各竞争初生相的析出次序。结果表明,Ａｌ－Ｆｅ合金快凝组织与成分及熔体的冷速有关,对一定成分的合金,当增加其熔体冷速时,亚稳ＡｌｍＦｅ相优先于Ａｌ６Ｆｅ相析出,初生α－Ａｌ相优先金属间化合物相析出,当合金中Ｆｅ含量越低,形成无一金属间化合物的相单－     

Al含量对Fe—Al无序固溶体性能的影响

本文应用余氏理论，对不同Ａｌ含量的富Ｆｅ区Ｆｅ－Ａｌ无序固溶体进行价电子结构计算和分析，从理论上探讨了Ａｌ含量合金晶格常数、原子磁矩、塑性以及晶体内原子状态的影响。研究发现，Ｆｅ－Ａｌ无序固溶体的晶格常数、原子磁矩和塑性随含Ａｌ的变化，是由于合金中Ｆｅ，Ａｌ原子之间相互作用导致原子状态发生变化的结果。     

STUDY FOR MECHANICAL ALLOYING OF Fe─M BY MOSSBAUER SPECTROSCOPY

将Ｆｅ－Ｍ（Ｍ＝Ｃ５ＳｉＯ２Ａｌ２Ｏ３）混合物在Ａｒ中高能球磨５６ｇ后测量Ｍｏｓｂａｕｅｒ谱，结果表明，（Ｆｅ）２－（ＳｉＯ２）１仍为Ｆｅ和ＳｉＯ２的机械混合物：（Ｆｅ）６－（Ｃ）３已完全合金化，生成两种Ｆｅ３Ｃ；（Ｆｅ）２－（Ａｌ２Ｏ３）１则成为Ｆｅ（７３％），尖晶石型的ＦｅＡｌ２Ｏ４）２２％），ｑｑｎｔＦｅ的团聚族（５％）和Ａｌ２Ｏ３的混合物。     

氩弧熔覆Fe-Al金属间化合物复合涂层的组织与性能

为改善Fe-Al金属间化合物的力学性能及抗高温氧化性能,利用氩弧熔覆方法在Q235钢上制备了Fe-Al熔覆层和Fe-Al/Al_2O_3熔覆层。采用金相显微镜、X射线衍射仪、硬度计、磨粒磨损试验机对氩弧熔覆涂层进行显微组织结构观察和磨损性能测试。采用高温氧化试验对涂层的耐高温氧化性进行了研究。结果表明:Fe-Al熔覆层形成FeAl和Fe_3Al相,而Fe-Al/Al_2O_3熔覆涂层含有FeAl、Fe_3Al和Al_2O_3相;熔覆层的耐磨粒磨损性能优于基体且Fe-Al/Al_2O_3熔覆层优于Fe-Al熔覆层;熔覆层的耐高温氧化性能明显提高,在700℃下,Fe-Al熔覆层和Fe-Al/Al_2O_3熔覆层相比于基体分别提高了4.46和5.68倍。     

Heteroepitaxial growth of Fe2Al5 inhibition layer in hot-dip galvanizing of an interstitial-free steel

This work presents characterization results on inhibition layers formed on a TiNb-stabilized interstitial-free steel after short time galvanizing. The Fe-Al and steel interface was free from oxide, so that the Fe-Al intermetallic compound could directly nucleate on ferrite grains. Electron diffraction performed in a transmission electron microscope showed that only Fe₂Al₅ was formed and it had a well-defined orientation relationship of [110]_{Fe(sub/2)Al(sub/5)}// [111]_Fe, (001) _{Fe(sub/2)Al(sub/5)}//(01?1)_Fe and (11?0) _{Fe(sub/2)Al(sub/5)}//(21?1?)_Fe with Fe substrate. The structure of the interfaces between Fe₂Al₅ and Fe is discussed. The epitaxially nucleated Fe₂Al₅ grains on Fe substrate had very small grain size, 20 nm or less, and several variants were intimately mixed. The grains grew rapidly to hundreds of nanometers toward the Zn side.     

Solid-state reactions underlying mechanochemical synthesis in the Fe-Al system

The sequence of solid-state transformations in the mechanochemical synthesis of Fe-Al intermetallics according to the reactions Fe + Al = FeAl, FeAl + 2Fe = Fe₃Al, and 2FeAl + 3Al = Fe₂Al₅ in powder mixtures has been studied by X-ray diffraction, differential scanning calorimetry, and Mössbauer spectroscopy. The results indicate that the process involves the formation of atomic configurations that may become nuclei of stable or metastable intermediate phases. Prolonged milling leads to homogenization of the synthesis product and the formation of a solid solution or an intermetallic phase with a low degree of long-range order. Complete ordering of the intermetallic phase can as a rule be achieved by heating.     

Fine structures in Fe3Al alloy layer of a new hot dip aluminized steel

The fine structure in the Fe-Al alloy layer of a new hot dip aluminized steel (HDA) was examined by means of X-ray diffractometry (XRD), electron diffraction technique, etc. The test results indicated that the Fe-Al alloy layer of the new aluminized steel mainly composed of Fe₃Al, FeAl and α-Fe (Al) solid solution. There was no brittle phase containing higher aluminum content, such as FeAl₃ (59.18% Al) and Fe2Al7 (62–93% Al). The tiny cracks and embrittlement, formerly caused by these brittle phases in the conventional aluminum-coated steel, were effectively eliminated. There was no microscopic defect (such as tiny cracks, pores or loose layer) in the coating. This is favourable to resist high temperature oxidation and corrosion of the aluminized steel.     

镁含量和硅对铁-锌铝镁合金固-液扩散偶中Fe-Al反应层的影响

在热浸镀锌中,铁基表面Fe-Al化合物层的形成会影响镀层的生长和质量。将Fe/(Zn-11%Al-3%Mg)和Fe/(Zn-11%Al-x%Mg-0.2%Si)扩散偶在600℃下进行25min的固-液扩散实验,利用扫描电子显微镜(SEM)和能谱仪(EDS)研究了镁含量和硅对铁-锌铝镁合金固-液界面Fe-Al合金层形成的影响。结果表明,Fe/(Zn-11%Al-3%Mg)固-液扩散偶反应层由FeAl3和Fe2Al5相层组成;随着Mg含量的增加,Fe/(Zn-11%Al-x%Mg-0.2%Si)扩散偶中反应层的厚度呈现先增加后减少再增加的变化趋势,当镁含量为3%时反应层厚度最薄;Fe/(Zn-11%Al-3%Mg)扩散偶中Fe-Al反应层的平均厚度比Fe/(Zn-11%Al-3%Mg-0.2%Si)扩散偶中反应层的厚度大60μm,证明Si元素起到抑制Fe-Al反应层形成的作用。研究结果为解释Super Dyma合金镀层中不形成明显的Fe-Al抑制层提供了实验依据。     

B2 Fe-Al合金中与空位有关的弛豫

利用内耗方法对空冷B2 Fe-Al合金中原子缺陷的运动特征进行了研究.在210℃(称为P1峰)和410℃(称为P2峰)附近观察到两个与样品热空位浓度密切相关的弛豫型内耗峰.研究表明,P1峰产生于应力作用下双空位(V_(Fe)V_(Al))的重新取向,而P2峰起源于反位置原子与Fe空位之间的相互作用.对于富Fe的B2 Fe-Al合金,P2峰产生于应力作用下三倍体缺陷(2V_(Fe)Fe_(Al))的重新取向;而对于富Al的B2 Fe-Al合金,P2峰则产生于应力诱导下Al反位置原子在Fe空位之间的运动.     

Characterization of Fe-supersaturated Fe-Al bronze coatings fabricated by magnetron sputter deposition

Magnetron sputter deposition was used to fabricate thin films of several Fe-Al bronze alloy compositions. Electron microscopy and X-ray diffraction were employed to evaluate the structure and composition of the films, and to determine the extent of Fe supersaturation. It was found that magnetron sputtering is an effective method for creating Fe-Al bronze alloys supersaturated with Fe. The maximum Fe content obtained in a sputtered film was 9.8%, well above the normal equilibrium solubility limit of 3.5 %.     

Mechanical alloying of Fe-Al intermetallics in the DO3 composition range

Binary Fe-Al intermetallics with compositions ranging between 10 and 30 at% have been produced by mechanical alloying. The elemental powders were milled together resulting in the dissolution of the Al atoms into the Fe lattice. Subsequent heat treatment of the compacted powder resulted in the formation of the intermetallic. However, complete suppression of the DO₃ (Fe₃Al) structure in favour of the B2 (FeAl) structure was observed. The suppression of the DO₃ structure is considered to be due to the presence of the high density of defects resulting from the heavy deformation incurred during milling. At Al compositions below 22 at%, X-ray diffraction revealed a b c c phase with lattice parameters varying between those of -Fe and the B2 intermetallic. The structure tended towards that of -Fe with lower Al contents indicating a decreasing number of Al atoms available to occupy B2 lattice sites. A fine grain size and evidence of tearing indicate that mechanically alloyed Fe-Al intermetallics in the DO₃ composition range are ductile at room temperature.     

Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

Low and medium carbon steels were aluminized by the pack aluminizing technique using halideactivated pure-Al and Fe-Al packs. The effect of mixture composition, aluminizing temperatureand time and C content of the steel substrate on the structure and thickness of the aluminidelayer, and on the oxidation resistance was investigated. The optimum oxidation resistance canbe achieved with a low carbon steel substrate when the intermetallic phases Fe3Al and FeAlform the surface of the aluminide layer. In this case, the Al concentration at the surface of thealuminide coating is at least ≥15 wt pct. Formation of high Al concentration phases (FeAl3 andFe2Al5) during aluminizing should be avoided as they tend to embrittle the aluminide layer andreduce its oxidation resistance.     

铁铝焊接界面组织与性能的研究

为了研究热处理对铁铝焊接界面组织和性能的影响,本文采用电容储能焊得到铁铝焊接接头,并对部分焊接接头进行热处理。利用显微镜、X射线能谱仪和显微维氏硬度仪对未热处理和热处理的焊接接头界面处的微观组织、化学成分和性能进行对比和分析。结果表明:热处理后焊接接头界面处有Fe-Al金属间化合物生成;热处理后的焊接接头融合区的铝含量比未热处理的低;焊接接头界面处由于铁铝原子的互扩散,硬度较铁、铝基体有所提高;热处理的焊接接头界面处的硬度高于未热处理的界面处硬度。热处理促使金属间化合物的生成,有利于改善焊接接头性能。