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1.
The short fatigUe cracks for aluminum-lithitim alloys are mainly in the field of mechanicalcharacteristic research [l--31. It is found thataluminum-lithium alloys eallibit the strongershort crack effect, which is difficult to overcome. In this icicle, the thresholds of short fatigUe cracks for alUminUm-lithium alloys 2090and 2090 Ce have been quantitatively stUdiedand evaluated. By adding Ce into alloy 2090, thebeneficial influence over the microstrUcture andproperties can be achieved [4, 5… 相似文献
2.
R. P. Martukanitz C. A. Natalie J. O. Knoefel 《JOM Journal of the Minerals, Metals and Materials Society》1987,39(11):38-42
The development of low-density aluminum-lithium alloys for aerospace applications provides industry with an attractive alternative to fiber-reinforced composites for reducing weight while maintaining the fabrication cost advantages of aluminum. In this study, gas metal arc (GMA), gas tungsten arc (GTA), and electron beam (EB) welding processes were used to evaluate the potential fusion weld-ability of alloy 2090 (Al-2.2 Li-2.7 Cu-0.12 Zr). The results indicate that, with proper filler alloy selection, 2090 may be easily welded with a low sensitivity to weld solidification cracking. The weld porosity of 2090, the source of which is hydrogen enriched surface oxides, may be eliminated by chemically or mechanically milling the surface prior to welding. The dominant modification in the heat-affected zone of 2090 weldments is dissolution of strengthening phases. This degradation is reduced by the use of high energy density heat sources, such as an electron beam, or post-weld thermal treatments. 相似文献
3.
1 IntroductionTherehavebeenconsiderableinvesti gationsonoptimizingstrength ductilitycombinationforaluminum lithiumalloysinrecentyears[1~ 3].Therelationshipamongtheprecipitatephases ,precipitatesfreezones (PFZ′s) ,equilibriumphasesatgrainboundaries ,andtensilep… 相似文献
4.
研究了稀土元素Ce、时效处理以及Al-Li合金表面形 成的贫化层对其剥蚀性能的影响.结果表明,2090合金中加入微量Ce可明显提高其耐剥蚀 性能,但过量则有害.因Al-Li合金的剥蚀抗力与时效过程中T1相析出有密切关系,所以在近 峰值时效状态,合金的剥蚀敏感性较高,欠时效和过时效状态,合金的剥蚀敏感性较低.此 外Al-Li合金表面贫化层能提高其抗剥蚀性能. 相似文献
5.
铝锂合金强化和韧化的特殊机理 总被引:1,自引:0,他引:1
以未再结晶晶粒结构的2090+Ce铝锂合金板材为对象,从铝锂合金与普通铝合金力学行为的主要差别入手,以揭示经典理论难以解释的现象为目的,重点研究了该合金独有的精细结构与断裂特征的内在联系,以及力学行为对之的响应关系。涉及到室温拉伸行为,疲劳长、短裂纹扩展特性,断裂韧性,光滑疲劳极限 相似文献
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The microstructure of dislocation in two kinds of aluminum-lithium alloys 2090 and 2090 + Ce was observed by means of TEM technology. The contributions of δ' and T1 precipitates to strength were separately calculated by using the results of quantitative metallography and analysis of micro-deformation behavior; the co-strengthening effect of δ' and T1precipitates was studied. The results show that the adding relationship of co-strengthening of δ' and T1 is in accordance with q = 1.4 form at the near peak-aged condition, i.e., △τ1.4 p = △τ1.4 δ' + △τ1.4 T1; but the adding relationship is approximately a linear relation (q = 1) at the under-aged condition and becomes the parabola form when over-aged (q = 2). The adding relationship of co-strengthening contribution of δ' and T1 is obviously dependent on aging time. 相似文献
7.
The effect of thermal processing following superplastic forming on the tensile properties of aluminum-lithium alloys is addressed.
The starting materials consisted of alloys 8090, 2090, and X2095 (a Weldalite™ 049 variant) in the form of commercial- grade
superplastic sheet. Experience dictates that post- forming practices aimed at a slightly underaged T6 temper produce balanced
engineering proper-ties in these alloys. The objective of this study was to assess the potential to use a T5- type temper
by elimi-nating the solution heat treatment and/or cold water quenching steps characteristic of T6 processing. The experimental
procedures adopted ensured that the tensile properties compiled were representative of the bulk material Initially, the strengthening
behavior of each alloy as a function of temper selection was established. Subsequently, aging practices that resulted in peak
strength and balanced properties were identified for the baseline T6 temper and two T5 tempers. The implications for replacing
a T6 tem-per with a T5- type temper, including rapid and slow cooling following forming, are discussed on the basis of the
results. 相似文献
8.
采用室温拉伸和Kahn撕裂测试方法,对一种加入不同含Ce量的新型Al-Cu-Li合金在T6态和T8态峰时效时的力学性能分别进行了测试;同时辅以扫描电镜和透射电镜对其断口形貌和晶界析出相相应的变化规律进行了研究。对所有状态样品的断口扫描照片和晶界析出相情况进行了统计。结果表明:T8态的强度值和UIE值(unit initiation energy)总体高于T6态,中等含Ce量的合金在T8态具有最高的强韧性配合。断口分析中发现:具有韧窝环绕金属间化合物特征的区域所占面积分数的变化趋势与UIE值变化规律一致;晶界分析表明:无析出带宽度的大小、晶界析出相的数密度和有效尺寸的变化决定了样品在不同Ce含量和热处理状态下的断裂阻力和裂纹扩展方式。 相似文献
9.
采用焊缝合金化手段,通过设计新型焊丝向焊缝中添加Li、Zr和Ce等合金化元素,研究了2090Ce稀土铝锂合金焊缝金属的热裂纹敏感性;探讨了合金元素对接头力学性能的影响及作用规律;进而研究了适用于焊接2090Ce合金的焊丝合金成分。试验结果表明,向焊缝金属中添加适量的合金元素Li、Zr和Ce,能够细化晶粒;增加焊缝中的共晶数量并改善其分布形态,从而有助于降低焊缝金属的热裂纹敏感性。另外,适量的Li、Zr和Ce等合金元素还能够在不降低接头塑性的同时,明显改善接头的强度;但Li和Ce含量过多则会对接头性能,特别是塑性造成损害。所设计的焊丝材料能够适用于焊接2090Ce稀土铝锂合金。 相似文献
10.
1IntroductionAloy2090isoneoftherelativelyweldevelopedhighstrength,heatresistantseriesamongcommercialAlLialloys.Theavail... 相似文献
11.
采用扫描电子显微镜,X射线能谱,Tafel极化曲线和电化学阻抗谱法研究了铈镧转化膜对AZ63镁合金耐蚀性能的影响。结果表明,铈和镧的复合转化膜比单一稀土膜的表面更加均匀致密,对镁合金的耐蚀性有明显改善。双稀土转化膜的缓蚀效果随着浸泡成膜时间的增长而增加。延长时效时间有助于铈和镧的进一步氧化,耐蚀性能先增后减,时效48 h膜层的耐蚀效果最好。 相似文献
12.
电场处理的强化晶界效应与唯象理论 总被引:13,自引:1,他引:13
以2090+Ce铝锂合金为研究对象,重点探索了电场处理的强化晶界效应,研究了室温拉伸性能、显微组织对之的响应关系。结果表明,电场固溶处理可强化晶界,从而减弱沿晶断裂倾向,获得改善塑性的效应,但对强度影响甚微。唯象理论研究表明,电场有助于增强晶内溶质固溶能力,阻碍溶质、空位簇聚。 相似文献
13.
AbstractStiffening of Al alloy aircraft structures with carbon fibre reinforced plastic laminate called ‘patches’ is considered as a viable option to enhance fatigue life. Interface so created between the reinforcement and Al alloy structure is potential site for crevice corrosion attack. Therefore, studies were conducted to investigate the interface corrosion behaviour of peak and two-step aged Al–Zn–Mg–Cu–Cr alclad alloy with and without the patch and examine the possibility to control the interfacial attack with the addition of cerium chloride inhibitor exposed to 3·5 wt-% NaCl solution for the durations of 2 and 168 h. Electrochemical impedance spectroscopy revealed that the interface attack was significantly reduced by the addition of 1000 ppm cerium chloride. The response of the peak and two-step aged alloy for such an addition was further investigated and found that the alloy under step aged condition behaves better than that of the peak aged condition. 相似文献
14.
铝锂合金作为轻质金属材料,具有优良的综合性能,因此应用前景十分广阔.从铝锂合金的焊接性出发,分别对铝锂合金弧焊,高能束焊,搅拌摩擦焊,扩散焊以及钎焊的研究现状进行了讨论.结果表明,采用各种焊接技术均可实现铝锂合金的焊接.分析了采用各种焊接技术焊接铝锂合金时的优势以及不足,并对各种焊接技术所获得接头的性能以及工艺改进措施进行了研究.针对目前各种焊接技术急需解决的问题以及铝锂合金焊接的发展方向,总结出了今后铝锂合金焊接研究的重点内容,并对铝锂合金焊接前景进行了分析与展望. 相似文献
15.
ZHAO Zhilong LIU Lin CHEN Zheng 《稀有金属(英文版)》2006,25(3):197-201
The microstructure of dislocation in two kinds of ahiminum-lithium alloys 2090 and 2090 + Ce was observed by means of TEM technology. The contributions of δ' and T1 precipitates to strength were separately calculated by using the results of quantitative metallography and analysis of micro-deformation behavior; the co-strengthening effect of δ' and T1 precipitates was studied. The results show that the adding relationship of co-strengthening of δ' and T1 is in accordance with q = 1.4 form at the near peak-aged condition, i.e., △τ^1.4δ = △τ^1.4δ+ △τ^1.4T1, but the adding relationship is approximately a linear relation (q = 1) at the under-aged condition and becomes the parabola form when over-aged (q = 2). The adding relationship of co-strengthening contribution of δ' and T1 is obviously dependent on aging time. 相似文献
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18.
Al-Li合金在EXCO溶液中腐蚀的电化学阻抗研究 总被引:10,自引:0,他引:10
研究了T6态峰时效AA2090及AA8090A1—Li合金在EXCO溶液中腐蚀的电化学阻抗持征.结果表明,剥蚀发生之前,AA8090合金电化学阻抗谱由一个压缩的高频容抗弧和一个低频感抗弧组成,且低频感抗成分随浸泡时间延长而减弱并消失;一旦发生剥蚀,其电化学阻抗谱即由一个高频和一个低额两个容抗弧组成.而AA2090合金在较短浸泡时间内由于较大面积蚀孔的产生,其电化学阻抗谱上即出现一个高频及一个低频两个容抗弧.发生剥蚀后,两种合金具有相同的电化学阻抗持征. 相似文献
19.
采用粉末冶金技术制备了不同Si含量(0,0.1,0.3wt%Si)的Mo-Si合金板材,并在25,300,800和1200℃下进行了静拉伸试验,研究了试验温度对Mo-Si合金板材力学性能、断裂方式及微观组织的影响。结果表明:随试验温度升高,纯钼及Mo-Si合金板材强度明显下降,但延伸率以300℃为分界点呈现出先升后降的趋势。室温下Mo-Si合金的断裂方式为穿晶解理断裂,在300及800℃时主要为韧窝延性断裂,而1200℃时为沿晶断裂。对Mo-Si合金强化机制的分析表明,室温下的强化主要来源于弥散强化和固溶强化,而在高温时,固溶作用明显减弱,颗粒弥散和粗化晶粒为主要的强化手段。 相似文献
20.
1.IntroductionItispossiblethatbifurcatinganddeflectingduringthecrackpropagationanddelaminatingonthefracturesurfacecancauseanadditionaltougheningbehaviourfortheengineeringmaterials.Theadditionaltougheningbehaviourfromthesefracturepatternsbelongstotheextrinsictougheningscope.Theextrinsictougheningandthenaturaltoughening,ortheintrinsictoughening,arethedecisivefactorsforthetotaltoughenillglevelofthematerials.Ingeneral,thetotaltougheninglevelcanbeobjectivelyreflectedbythematerialfracturetoughness.… 相似文献