镍基耐蚀合金复合板的制备及结合机理研究

本文介绍了目前用于镍基耐蚀合金复合板的热轧和冷轧制造工艺,分析了轧制复合的机理并比较了目前适用界面结合的再结晶理论、金属键理论、能量理论、扩散理论、位错理论和三阶段理论,最后分析了该种类型复合板的应用前景.     

Coarsening of γ (Ni–Al solid solution) precipitates in a γ′ (Ni3Al) matrix; a striking contrast in behavior from normal γ/γ′ alloys

Coarsening of γ precipitates in a γ′ (Ni₃Al) matrix depends strongly on volume fraction, in dramatic contrast with coarsening of γ′ precipitates. Coalescence of γ precipitates is easy, unlike the resistance to coalescence of γ′ precipitates. We regard this as indirect proof that anti-phase relationships among γ′ precipitates inhibit coalescence.     

环件冷辗扩技术现状和发展

介绍了环件冷辗扩原理、冷辗扩工艺、冷辗设备、加工过程控制参数、模具寿命及有限元模拟技术的现状和发展。文中指出了环件冷辗扩还缺乏精确而系统性的研究,弹塑性有限元研究才刚刚起步,而在我国还是一个空白。同时,通过模拟来优化加工过程参数在国际上也几乎没有公开发表的文献。因此,应该从理论、有限元模拟、材料、设备、热处理、模具等多学科联合攻关研究,才能使我国的环件冷辗扩技术跃上一个新的台阶。     

极薄带微轧制中的系列新发现

在对极薄带微轧制的研究中,陆续发现一系列用传统轧制理论不能解释的新现象,如工业纯铜的超延展现象、脆性材料的非典型塑性现象、异种金属多层复合中的变形诱导反应扩散现象等。这些新现象与微成形中的尺寸效应有关,对其进行深入研究,一方面,能够有助于揭示微成形的深层规律,加深对塑性变形本质的认识;另一方面,有助于在微成形领域产生新思路,开发微成形新工艺,促进微成形产品开发,推动微成形技术的进步。     

异步轧制对高纯铝箔冷轧织构的影响

通过异步轧制，对高纯铝箔微取向流变行为进行了研究，结果表明，异步轧制与同步轧制的冷轧织构有较大差异，高纯铝箔在异步轧制下慢辊和快辊两侧的织构类型明显不同，尤其是旋转立方织构{001}{110}在含量上的差异更大，快辊侧随形变量的增中冷却织构主要为：S织构和{102}{uvw}织构，而慢辊侧则主要为：旋转立方织构{001}{110}，慢辊侧的旋转立方织构在相同的速比、相同的形变量下一般要大于快辊侧的旋转立方织构。     

铸型用焓变涂料材料的研究

对几种物质化学反应过程中的温度变化进行定性实验,选出其中效果较好的几组物质,进行差热分析(DTA),定量测出这些物质的化学反应温度。由焓变涂料效果测试实验得出,碳酸钙、碳与氧化锌、碳与碳酸钠涂料是3种吸热涂料,其中碳酸钙涂料吸热效果最好;碳酸钙与镁、氧化铁与镁、氧化铁与锌涂料是3种放热涂料,其中前两者效果更好。     

同步异步轧制对高压阳极铝箔织构的影响

简述同步和异步轧制工艺的特点,对比了不同轧制工艺对高压阳极铝箔冷变形及再结晶织构的影响.结果表明,同步、异步轧制铝箔退火后都可得到高的立方织构含量,但后者的压力小,生产成本低,采用异步轧制生产高压阳极铝箔,可以调整传统的高压阳极铝箔生产工艺,降低生产成本.     

Effects of rolling technical factors on microstructures and mechanical properties of aluminum foils

1　INTRODUCTIONInthealuminumfoilsrollingprocess ,therawstripsusuallyarerolledfrom 0 .30 .7mmdownto6 .0 0 6 .5 5 μm through5 6rollingpasses ,sodou ble zeroaluminumfoilsrollingbelongstoultimaterollingcategory .Intherollingprocess ,therationali tyoftechnicalparametersandthestructurepropertiesofaluminumfoilsitselfhaveprominentinfluenceonthecomprehensivefinalproductratioandthenumberofpinholes .Recentdecades ,manyscholarsandengi neershaveinvestigatedthetechniqueofaluminumfoilsmanufacture ,andth…     

几何因素与摩擦耦合对高纯铝箔剪切织构的影响

采用取向分布函数 (ODF)研究了轧制几何因素、轧制摩擦条件对高纯铝箔轧制织构的影响。结果显示 ,如果轧制摩擦因数大 ,当处于均匀变形几何条件 1相似文献   

Influence of Pt on the metal-oxide interface during high temperature oxidation of NiAl bulk materials

The purpose of the investigation was to study the mechanisms improving oxide scale adherence in Pt-free and Pt-rich β-NiAl materials during high temperature oxidation. Theoretical density-functional theory (DFT) calculations were used to calculate the work of separation of the β-NiAl(1 1 1)/α-Al₂O₃(0001) metal-oxide interfaces, in pure NiAl and Pt-rich NiAl materials. The experimental work was focused on the studies of the metal-oxide interface, its development and morphology. Based on the theoretical and experimental results a complementary picture is presented for a better understanding of the Pt effect on the oxidation and oxide adhesion. It is shown that the interfacial bonding is decreased with addition of Pt to β-NiAl. The beneficial effect of Pt on the adhesion energy is attributed to the enhancement of contact areas between the oxide and the metal. The influence of Pt on the diffusion of Al and the formation of interfacial voids is also discussed.     

邦迪管用高精密冷轧钢带的生产特点

文章介绍了该公司生产邦迪管用高精度冷轧带钢的生产设备情况及工艺特点，提出了提高邦迪管用高精度带钢的一些关键工艺问题。     

异步轧制高纯铝箔冷轧织构沿板厚的分布规律

通过异步轧制, 研究了高纯铝箔冷轧织构沿板厚的分布规律。 在异步轧制下, 快、 慢速辊侧之间的各中间层的织构类型不同。 速比为1.28, 形变量为99.2%时, 随厚度的增加, 呈现出极有规律的变化: ｛100｝丝织构含量近线性减少, 而｛112｝, ｛102｝, ｛123｝丝织构含量近线性增加。当形变量为99.2%时, 在不同速比下{001}丝织构含量沿厚度变化趋势不同: 速比1.28时, 呈现出近线性递减; 速比1.17和1.06时, 总的趋势也是递减, 且在厚度d＝0.04mm处有最小值。     

Formation of NiAl intermetallic by gradual and explosive exothermic reaction mechanism during ball milling

NiAl intermetallic has been produced by mechanical alloying in a high energy vibrator mill using elemental Ni and Al powder mixture. The NiAl powders were formed in two ways. One by a gradual exothermic reaction mechanism during a long time continuous milling and the other by explosive exothermic reaction mechanism that occurred when opening the milling vessel to the air atmosphere after a short time milling. Prolonged milling for both cases resulted in change of morphology and refinement of grain size down to nano scale.     

金属环件冷辗扩数值模拟中圆度辊定位的研究

金属环件冷辗扩具有很好的发展潜力，而我国在该领域尚处于起步阶段。对金属环件冷辗扩数值模拟可以预测环件的塑性变形和受力情况，进而对工艺改进或者模具修改有参考作用。本文对辗扩中对圆度辊的定位问题进行了分析，并较好地实现了模拟效果。     

Thermodynamic activity measurements in the B2 phases of the Fe–Al and Ni–Al systems

The vaporisation of Fe–Al and Ni–Al alloys has been investigated in the temperature range 1140–1600 K and 1178 to 1574 K, respectively, by Knudsen effusion mass spectrometry (KEMS). Eleven different Fe–Al and also eleven Ni–Al compositions have been investigated in the composition ranges 30–51 at.% Al and 38–53 at.% Al, respectively. The Fe–Al samples have been investigated mostly in the B2 region of the phase diagram. The partial pressures and thermodynamic activities were evaluated directly from the measured ion intensities formed from the equilibrium vapour over the alloy and the pure element. From the temperature dependence of the activities the partial and integral molar enthalpies and entropies of mixing have been obtained. These are the most accurate data obtained by mass spectrometry on Fe–Al and Ni–Al systems so far. Nearly temperature independent integral enthalpies and entropies of mixing over the wide temperature range investigated were found, with the mixing entropies being large and negative.     

Effects of aluminum concentration and compact thickness on reaction synthesis of Ni3Al---NiAl alloys

The effects of aluminum concentration and green compact thickness on the reaction synthesis of powder compacts containing 25 to 40 at. %Al were studied under a uniaxial compressive stress of 10 MPa. The results indicate that both reaction product and material density are sensitive to these two parameters. For all powder compacts with a thickness of 5 mm, no temperature increase was detected during reaction synthesis, indicating no formation of transient liquid phases and thus no self-sustaining combustion reaction. For 6- and 7-mm-thick compacts containing 40% Al, a full synthesis reaction took place, resulting in production of the NiAl alloy with a high material density (>98%) and a fine grain size (14 μm). Other compacts containing 25 and 30% Al showed a coexistence of partially and fully reacted zones, with the reaction zone size strongly dependent on aluminum concentration and compact thickness. All the results are discussed in terms of local heat accumulation and heat transfer as well as thermodynamic analyses of exothermic reactions during each reaction step.     

Notch sensitivity of heavily cold-rolled Ni3Al foils

The notch sensitivity of 95% cold-rolled Ni₃Al foils was examined using double U-notched tensile specimens. The foils were found to be essentially insensitive to the presence of the notch. Plastic deformation occurred locally at the notch root to relieve the stress concentration, resulting in the notch insensitivity.