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胶接接头耐久性的综合研究 总被引:2,自引:0,他引:2
以AG—80/DDS、环氧—聚砜和环氧—丁腈结构胶为胶粘剂,45~#钢和LY_(12)—CZ铝合金为被粘材料,综合研究了胶接接头的耐久性。研究结果表明,除胶粘剂外,内外应力、温度、介质和被粘物的表面状态均是影响接头耐久性的重要因素。激光双折射法测定胶接接头内应力是较可行的新方法。 相似文献
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选取J-133环氧结构胶黏剂,制备铝合金胶接接头。通过在湿热条件下对试样进行环境试验,对结构胶黏剂和胶接接头的耐久性进行了评价。采用TG、IR和光学显微镜分别对胶黏剂样品变化和胶接接头破坏面形貌进行分析。分析结果表明:该胶黏剂在55℃和80℃,2200h湿热老化后剪切强度下降分别超过5%和7%;胶黏剂热失重峰温度下降,发生了断链分解;断链反应发生在固化生成的新官能团部位;胶接界面层和胶黏剂层都受到了水分的影响。 相似文献
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结构胶胶接接头耐久性的研究进展 总被引:1,自引:0,他引:1
结构胶是胶黏剂中具有高强度、耐高温、高耐久特性的一类胶黏剂的总称,主要用于部件中承受载荷的胶接连接。胶接接头的耐久性能是结构胶应用中的一个重要指标。主要从影响胶接接头耐久性的内在因素和外在因素以及实验室研究方法对结构胶胶接接头耐久性的研究进展进行综述。 相似文献
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采用LY12铝合金材料在Ansys12.0软件平台上建立环氧树脂胶粘剂双搭接胶接接头有限元模型进行分析,着重考察了在冲击载荷作用下胶层厚度的改变对胶接接头应力分布的影响。研究结果表明:在一定范围内,随着胶层厚度的增加,胶接接头中最大应力值逐渐下降,而最小应力值开始先下降,在胶层厚度为0.4 mm时最小,之后应力值又继续增大,且最大应力值总是出现在胶层界面的边缘处;在冲击速率为3.4 m/s时,胶接接头在0.4、0.6 mm的胶层中节点的轴向应力Sx、剥离应力Sy、剪切应力Sxy、第一主应力S1、等效应力Seqv随着胶层厚度的增加,波动范围变窄,应力峰值也变小,而胶层厚度为0.2 mm时应力值波动异常剧烈,峰值很大。 相似文献
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受集中载荷作用的金属胶接接头应力分布研究 总被引:3,自引:0,他引:3
分析了金属胶接接头受集中载荷作用下应力分布的一般模型,指出了其局限性和不足。借助于金属试样表层的显微硬度测定及应变片电测法间接确定了胶接接头承受不同的载荷作用时接头上的实际应力分布,结果表明胶层中存在着较宽的分布拉伸应力。作者根据实验结果提出了金属胶接接头在集中载荷作用下肢层内应力分布的修正模型。 相似文献
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本文描述了老化和环境因素对胶接接头性能影响的耐久性方案试验结果.文中报导的结果是将试样在不同的和环境条件下贮存8—9年测得的.在环境因素,尤其在高度潮湿和自然暴露条件下,一些接头表现出很好的耐久性能.而另一些接头情况相反.我们发现老化对静态和疲劳性能的影响未必如此. 相似文献
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在讨论现有劈裂的力学模型基础上,建立了一个新的劈裂力学模型,以较好地描述在接头的胶层内的应力分布及力行为。认为载荷是以分布力的形式作用在胶层上的,该模型还可用于解释一些试验所得的结果。 相似文献
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A. Raveh D. Marouani R. Ydgar J. E. Klemberg-sapieha A. Bettelheim 《The Journal of Adhesion》1991,36(2):109-124
Aluminum plates (type 2024) were subjected to various surface pretreatments and then joined by epoxy resin. The joints were tested for shear strength close to the time of joining, and after various storage periods at 25±5°C and 40% relative humidity. Surfaces of the aluminum plates were examined using X-ray photoelectron spectroscopy, and scanning electron and optical microscopies. Specimens examined shortly after being joined showed a trend of cohesive failure, but those which were stored for some time showed a trend of adhesive failure. It was found that the mean shear strength (MSS) of the specimens treated by a chromic acid solution was lower than that of specimens treated by a phosphoric acid solution. Hardness (Shore type D-2) and structure (by X-ray diffraction) of epoxy control samples were also examined. It was observed that the hardness increases with longer aging time, while changes in the structure were observed after long-term storage (63 months). The failure development with time is discussed and correlated with the MSS and the failure mode. 相似文献
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Factors Affecting the Durability of Ti-6Al-4V/Epoxy Bonds 总被引:1,自引:0,他引:1
Factors influencing the durability of Ti-6Al-4V/epoxy interphases were studied by determining chemical and physical properties of Ti-6Al-4V adherend surfaces and by characterizing the strength and durability of Ti-6Al-4V/epoxy bonds.
Ti-6Al-4V adherend surfaces were oxidized either by chemical etch or anodization. Four principal pretreatments were studied: chromic acid anodization (CAA), sodium hydroxide anodization (SHA), phosphate fluoride acid etch (P/F) and TURCO basic etch (TURCO). The oxides were characterized by SEM, STEM, profilometry, contact angles and XPS.
All adhesive bonding was carried out using a structural epoxy, FM-300U. Both lap shear and wedge test samples were tested in hot, wet environments. The results lead to the conclusion that the interfacial area between the adhesive and adherend is the primary factor affecting bond durability. 相似文献
Ti-6Al-4V adherend surfaces were oxidized either by chemical etch or anodization. Four principal pretreatments were studied: chromic acid anodization (CAA), sodium hydroxide anodization (SHA), phosphate fluoride acid etch (P/F) and TURCO basic etch (TURCO). The oxides were characterized by SEM, STEM, profilometry, contact angles and XPS.
All adhesive bonding was carried out using a structural epoxy, FM-300U. Both lap shear and wedge test samples were tested in hot, wet environments. The results lead to the conclusion that the interfacial area between the adhesive and adherend is the primary factor affecting bond durability. 相似文献
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The durability of aluminum/epoxy adhesive joints prepared from substrates pretreated by plasma etching and then deposition of plasma-polymerized primers was determined using the wedge crack testing method. Plasma etching and polymerization were conducted using both direct current (DC) and microwave (2.45 GHz) driven plasma systems. Plasma-polymerized primers were deposited using trimethysilane (TMS) and hexa-methyldisiloxane (HMDSO) to form siloxane-like and silica-like films, respectively. Plasma etching with argon and argon/hydrogen plasmas was used as a substrate pre-treatment. In some cases etching with an oxygen plasma was used as a post-treatment to give a silica-like surface to siloxane-like films deposited from TMS. Adhesive joints were prepared using two different epoxy adhesives, Cytec FM-300 and FM-123-2. Differences in initial adhesion were observed for primer films with chemical differences. Siloxane-like primer films were not wetted by the adhesive and resulted in poor wedge test results. Silica-like primer films were not wetted by the adhesive and resulted in poor wedge test results. Silica-like primer films deposited onto aluminum substrates resulted in wedge specimens with good adhesion and durability. The initial crack was cohesive within the adhesive. However, crack growth occurred at the interface between the adhesive and silica-like primer. Durability of the wedge specimens was essentially invariant of the type of microwave plasma pretreatment for grit-blasted aluminum substrates that were coated with silica-like primers before bonding with FM-123-2. 相似文献
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制备了四种环氧树脂(E-51、AG-80、AFG-90、TDE-85)及其复合树脂体系的液体丁腈橡胶CTBN改性胶黏剂,研究了这些胶黏剂及加入不同质量的TDE-85和AFG-90后的粘接性能。研究结果表明,TDE-85对改性胶的室温剪切和剥离强度贡献较大,AFG-90对高温剪切强度贡献较大。在TDE-85改性胶(TC-23)和TDE-85/E-51复合树脂改性胶(TEC-23)中,添加10%的AFG-90,可使它们的室温、100℃剪切及室温剥离强度分别达到37.4MPa、16.7MPa,65.4N·cm-1和33.7MPa、18.2MPa,60.0N·cm-1,具有较好的综合性能。 相似文献
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利用填充混合法制备了环氧树脂(EP)/炭黑(CB)复合材料,研究了CB对体系反应及性能的影响。使用扫描电镜对拉伸断口形貌进行了观察;利用透射电镜观察了CB在EP中的分散状态。结果表明:CB的加入使体系固化时的最高放热温度从179℃降到169℃,凝胶化时间变短;适量CB的引入提高了材料的拉仲强度、断裂伸长率和冲击强度,CB用量在2%时材料的综合力学性能最佳;随着CB用量的增加,复合材料的玻璃化温度也随之提高。 相似文献
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Luyi Sun Woong‐Jae Boo Jia Liu Abraham Clearfield Hung‐Jue Sue Nikhil E. Verghese Ha Q. Pham Jozef Bicerano 《大分子材料与工程》2009,294(2):103-113
The effect of nanoplatelets on the rheological behavior of epoxy monomers with variations in nanoplatelet exfoliation level and aspect ratio was investigated. The results show that the presence of exfoliated nanoplatelets in epoxy can significantly influence viscosity and lead to shear‐thinning phenomena, especially when the aspect ratio of the nanoplatelets is high. By employing the Krieger‐Dougherty model, the effectiveness of nanoplatelets in altering epoxy rheological behavior was quantitatively described and compared with experimental findings. Possible physical reasons for the observed rheological behaviors are discussed. The implication of the present study for polymer nanocomposites processing is also addressed.
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Steel/epoxy peel specimens were prepared using ethylene-mercaptoester (EME) copolymer coupling agents (90 wt% mercaptoester units) applied in thickness ranging from 25 to 350 Å. An optimum thickness of approximately 140 Å, which corresponded to an over 200% increase in peel strength when compared to 50 Å thick samples, was determined from ellipsometry and 90° peel strength measurements. The corrosion protection obtained was essentially independent of coupling agent thickness. 相似文献
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本文介绍了一种新型聚合物改性粘结砂浆(PMBM),并研究了聚合物对粘结砂浆性能的影响,测试了砂浆的抗冻性、粘结抗拉强度、收缩率和吸水率等性能;利用扫描电镜等观察了聚合物改性粘结砂浆硬化体的微观结构,分析了苯丙乳液对水泥砂浆的改性机理.研究表明,聚合物能降低砂浆的压折比、吸水率和收缩率,改善砂浆的抗冻性及耐久性.聚合物掺量为20%时,PMBMs压折比小于3.0,符合粘结砂浆对压折比的要求;PMBMs收缩率为0.0351%,远小于普通粘结砂浆;经6次冻融循环后,试样的质量损失和强度损失分别为0.22%和-18.7%;粘结抗拉强度(28 d)为4.4 MPa远高于普通粘结砂浆(0.82 MPa);扫描电镜显示PMBMs内部孔隙具有光滑的孔壁结构. 相似文献
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采用钛合金与芳纶纤维复合材料制备不同搭接长度的单搭接接头。利用数字图像相关技术(DIC)、万能试验机等表征方法,对接头拉伸应变与极限载荷进行表征,研究了搭接长度对异质材料单搭接接头胶接性能与破坏模式的变化规律。结果表明,随着搭接长度的增加,单搭接接头极限载荷提升,胶接强度降低,高搭接长度接头出现渐进损伤;偏心弯矩引起的接头偏移减少,搭接部位纵向应变区域面积占比降低;芳纶纤维复合材料层间破坏模式增多,钛合金-胶层界面破坏模式减少,剥离复合材料层数增加。 相似文献