铜包钢线加工工艺对其电阻率的影响

本研究采用包覆焊接法制备铜包钢线,并对其进行拉拔变形及退火处理。给出了经拉拔变形后的铜包钢线电阻率的计算公式。研究了不同的拉拔变形量和退火处理对其电阻率的影响;分析了其电阻率随加工工艺的变化规律。研究结果表明,铜包钢线的电阻率随其形变量的增加而升高。根据纯铜和钢丝原材料的电阻率,可计算经过不同拉拔变形量的导线的电阻率。随着铜包钢线退火时间的延长和退火温度的升高,其电阻率降低。通过实验数据分析,得到了铜包钢线的退火温度和退火时间分别与其电阻率关系的回归方程。     

冷轧与退火对LA91合金显微组织和力学性能的影响

对热挤压态LA91合金进行了冷轧及退火处理,研究了不同冷轧变形量与退火温度对合金显微组织和力学性能的影响。结果表明,总轧制变形量为76.7%的LA91合金薄板具有较高的强度和良好的塑性(抗拉强度为177 MPa,伸长率为37.4%)。在200~300℃范围内退火,冷轧LA91合金发生回复和再结晶,β相逐渐变为等轴状,α相逐渐球状化。因此,随退火温度升高,合金薄板的抗拉强度先降低后升高,伸长率则先升高后降低。同一变形量下,合金中的α相再结晶温度略高于β相;经1h退火,不同变形量的冷轧LA91合金开始再结晶的温度略微不同,约为250℃,退火温度为300℃时,再结晶完成。     

冷变形及退火工艺对617B合金组织性能的影响

研究了冷加工变形量、退火温度和退火时间对617B合金管材组织及力学性能的影响。结果表明:随着变形量的增大,晶粒沿着最大主变形方向被拉长,形成了长条状的形变带,合金室温抗拉强度和屈服强度逐渐提高,延伸率下降;当退火温度从1080℃提高到1160℃时,随着退火温度的提高,合金的晶粒逐渐长大,抗拉强度和屈服强度降低,塑性提高,退火温度到1160℃以上继续提高温度,晶粒长大速度明显增大,强度和塑性变化不大;不同变形量下合金晶粒长大的激活能Q均远大于纯Ni的自扩散激活能,且Q值随着变形量的增加先升高后降低;合金晶粒长大指数η值随着退火温度的提高先增大后减小。     

Cu对Ag-Ce合金组织与结构之影响

利用扫描电子显微镜和能谱仪分析Cu对Ag-Ce合金组织与结构的影响。结果表明：Ag-Cu-Ce合金基体为银铜固溶体,晶粒较小,基体上弥散分布着许多共生析出的β-Cu和Ag4Ce颗粒,Cu的加入改善了Ag4Ce的偏析现象。Ag-Ce和Ag-Cu-Ce合金的拉伸断口呈锥形,有明显的韧窝组织,为典型的韧性断裂。     

冷轧Cu-15Cr原位复合材料组织和性能研究

经冷轧变形和中间退火制备了Cu-15Cr形变原位纤维增强复合薄板材料。用SEM、拉伸试验机和电阻率测试仪研究了变形量及退火温度对Cr纤维形貌、合金强度及导电性能的影响。结果表明:随合金变形量的增加,Cr纤维逐渐变薄、变宽,纤维间距逐渐减小,材料的抗拉强度和导电率都逐渐增大。退火温度升高,材料抗拉强度随之降低,导电率先升高后降低,退火温度为550℃时,导电率峰值为84.4%IACS;退火温度升高,Cr纤维依次发生球化,球化加剧、纤维断裂。最终变形量时,材料达到较好的综合性能匹配,退火前抗拉强度和导电率为694 MPa和78%IACS;500℃退火后抗拉强度和导电率为570 MPa和83%IACS。     

Cu-14 Fe-C合金拉拔后的组织和性能

采用光学显微镜、扫描电镜、维氏硬度计等研究了真空熔炼制备Cu-14Fe-C合金不同应变量拉拔和不同温度退火处理后的组织、力学性能和导电性能,结果表明,铸态Cu-14Fe-C合金中碳元素主要存在于富铁相内部;拉拔使Cu-14Fe合金中富铁相由铸态时的树枝状随机分布趋向于沿拉拔方向分布,拉拔变形量越大,纤维状富铁相尺寸越细,分布也越均匀;拉拔使Cu-14Fe-0.2C合金中大部分近似球状富铁相逐渐转变为近似椭球状,拉拔变形量越大,近似球状相被拉长得越明显;拉拔变形显著提高Cu-14Fe-C合金的硬度而降低其电阻率; Cu-14Fe-C合金拉拔后退火,电阻率随退火温度提高不断下降。     

Ti-6242合金的热力学参数研究

利用G1eeble试验机研究了加热温度、应变速率对Ti-6242合金的变形抗力和塑性的影响；采用光学显微镜测试了在不同加热温度、变形量和退火温度条件下Ti-6242合金的α晶粒度。结果表明：锻造或退火的加热温度超过α＋β相区时，加热温度升高，晶粒长大非常迅速。     

Ti（50）Ni（47）Fe3形状记忆合金冷轧变形后的组织与性能

采用拉伸测试、维氏硬度测试、电阻率-温度曲线测试及扫描电镜和透射电镜观察显微组织的方法研究冷轧变形量为25%的Ti50Ni47Fe3合金经450-750°C下1 h退火后的显微组织和性能。结果表明,冷轧变形增强了合金的抗拉强度和屈服强度,冷轧变形后形成的应力场有助于R相变的发生。随着退火温度的升高,合金的抗拉强度和屈服强度下降,伸长率增大;当退火温度高于650°C时,强度和伸长率趋于稳定。电阻-温度曲线表明,在升、降温过程中发生两阶段相变B2-R-B19′。随着退火温度的升高,合金的相变温度降低;当退火温度高于650°C时,相变温度趋于稳定。随着退火温度的升高,合金依次发生回复、再结晶和晶粒长大。     

Cr20Ni35合金的晶粒尺寸对电阻率的影响

通过拉伸变形和再结晶退火改变Cr20Ni35合金的晶粒尺寸,研究晶粒尺寸对Cr20Ni35合金电阻率的影响。结果表明,Cr20Ni35合金经过拉伸变形后,随着伸长率的增加其电阻率出现递减的趋势,此时晶粒尺寸呈现递增的趋势;随后经过退火后,其电阻率值又重新升高,分析观察其金相组织,晶粒尺寸越小,电阻率越大。     

退火时间对Ti-49.8Ni形状记忆合金组织和形变行为的影响

用光学显微镜、X射线衍射仪及拉伸试验机研究退火态Ti-49.8Ni形状记忆合金的显微组织和形变行为.结果表明,冷加工和400 ℃退火态Ti-49.8Ni合金的组织呈纤维态,退火时间对合金组织影响不大.Ti-49.8Ni合金室温组成相主要为马氏体,随退火时间延长,400 ℃退火态合金弹簧的马氏体再取向应力先降低后升高,600 ℃退火态则升高.随形变温度升高,不同退火态合金弹簧的马氏体再取向应力升高,弹簧刚度增加.适合该合金变形加工的退火工艺为600 ℃×1 h.     

可加工变形的Au-Cu-Zn-Al形状记忆合金

报道了一种新的金基形状记忆合金(Au-Cu-Zn-Al)的初步研究,结果表明,成分配比合适的合金可以用常规的方法加工变形,有典型的热弹性马氏体相变及良好的单程和双程形状记忆效应。合金的金含量可达50wt％。     

高温形状记忆合金

马氏体逆相变开始温度As点稳定在120℃以上的形状记忆合金称之为高温形状记忆合金,有多种合金系可供选择。本文综述了现有的各种高温形状记忆合金系的研究现状。     

高强度金银钯铂铜合金的性能与应用研究

介绍了金银钯铂铜合金系列的成分、组织、性能及其应用研究。其综合性能优于国内外同类材料,等体积材料的成本低于同类材料的40～80％。该系列合金适用于航空、航天和航海技术中的各类线绕传感器、电位器,电阻器的绕组和电刷以及电接触器的接点、导电环和电刷。     

我国钛及钛合金研发与进展

我国材料工作者对不同领域使用的钛合金进行了卓有成效的研究工作。经过近50年的发展,我国的钛工业在科技和生产上都取得了长足进步。概述了我国自主研发的各种钛及钛合材料,包括高温钛合金、高强钛合金、低温钛合金、耐蚀钛合金、船用钛合金、医用钛合金等。最后对我国钛工业进行了简要的展望。     

Ag-Cu-In-Sn系低熔点钎料

研究一种新型银基钎料合金Ag—Cu—In—Sn,并提供其钎焊特性和钎接头的机械性能。此钎料具有较低蒸气压和熔化温度,钎焊接头具有较高的气密性,适用于电真空、半导体及微电子器件在真空或保护气氛中无钎剂钎焊。     

Compressive training of the shape memory alloy washer

This paper evaluates the performance and engineering aspects of 44Ti-47Ni-9Nb alloy in a pretensioning washer application. Previously the behavior of this alloy has mainly been studied for tensile predeformation with wires and strips up to 1 mm thickness. The present work investigated the effect of compression deformation and different homogenization temperatures on ring-shaped washers with larger dimensions. The best results with the compression-trained washer were achieved after homogenization at 1073 K where the compression training deformation was -10.4%, the lowest applied. The deformation training was carried out at 213 K near the martensitic reaction start temperature of the material. The expansion method, applied to the commercial reference ring, seemed to be a fairly efficient training method for the studied application, even though the parallel course of the radial surfaces was poor.     

MICROSTRUCTURE MODIFICATIONS OF WROUGHT AND CAST TiAl ALLOYS

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Stability of protective oxide films on Ti-base alloys

Thermodynamic calculations are performed to estimate isothermal sections of Ti-Al-O, Ti-Si-O, and Ni-Al-O phase diagrams. Very small aluminum levels (<10^–10 at. %) are needed to stabilize alumina on Ni-Al alloys. However, much higher aluminum (50%) and silicon (40%) levels are needed to stabilize alumina and silica on Ti-Al and Ti-Si alloys, respectively. These calculations suggest that the mechanism of formation of the protective oxide films on titanium-based alloys is radically different from that on nickel-based alloys. The aluminum levels needed to form a continuous film of alumina on nickel-based alloys are dominated by kinetic factors. On the other hand, thermodynamic factors appear to dominate the alloy compositions needed to form protective films of alumina and silica on titanium-based alloys. Further work is needed to evaluate any possible role of kinetic factors.     

Corrosion of iron-, nickel-, and cobalt-base alloys in atmospheres containing carbon and oxygen

The corrosion of iron-, nickel-, and cobalt-base alloys has been studied in atmospheres containing carbon and oxygen in the temperature range 894–1366 K. It was observed that preformed Cr₂O₃ films are not effective barriers to carbon transport in atmospheres in which the oxide is not stable but that stable, growing Cr₂O₃ films are excellent barriers to carbon penetration. The presence of Fe-containing oxides on Fe-Ni-Cr and Fe-Cr alloys cause the scales to be permeable to carbon. This phenomenon was found to be sensitive to alloy surface preparation. Carbon transport through oxide scales may occur by two mechanisms: diffusion or molecular transport through physical defects. The present work has evidence of the latter but cannot rule out the former in cases where the carbon activity is sufficiently large. In gases containing CO and CO₂ in which Cr carbide is stable Cr₂O₃ was found to form at the carbide-alloy interface by oxygen transport through the carbide. In A-CH₄ Fe-Ni-Cr were found to undergo graphitization attack. The results were consistent with the formation and subsequent decomposition of metastable carbides, as proposed by Hochmann.     

Pd—40Ag—1RE（Sm,Eu,Gd）合金的内氧化及其性能

研究了φ0.1～2.0mm Pd-40Ag-1RE(Sm,Eu,Gd)合金丝在800～1200℃大气气氛下的内氧化行为及其性能,其内氧化深度ξ与反应时间t的关系是ξ=kt~n,在低温下,符合内氧化抛物线规律.随反应时间延长,温度升高,n增大,对此规律偏离越大,三个合金内氧化n=0.5～0.75,Pd-40Ag-1Sm和Pd-40Ag-1Gd晶界局部超前氧化,合金内氧化由体扩散控制.