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电子部件封装用无铅焊接材料的研究动态 总被引:5,自引:2,他引:3
介绍了无铅焊接材料的研究背景,并以发展前景良好的候选材料Sn-Ag,Sn-Bi,Sn-Zn系共晶合金为例,介绍了无铅焊接材料的研究现状和存在的问题。研究表明,Sn-3.5%Ag基合金具有良好的力学性能,但熔点偏高;Sn-58%Bi基合金的机械性能略差,并且熔点太低;Sn-8%Z。基合金虽然有合适的熔点,但润湿性差。本文还简略地介绍了由日本开发的材料设计系统以及在无铅材料开发中的作用,并指出该材料设计系统将是开发无铅焊接材料中不可缺少的工具。 相似文献
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WCp/Fe—Ni钢基复合材料的抗热疲劳特性 总被引:4,自引:0,他引:4
对WC颗粒体积分数、颗粒尺寸在复合材料热疲劳过程中的影响进行了研究,并探讨了WC颗粒复合材料抗热疲劳特性的形成机理。结果表明,WC颗粒体积分数增加,复合材料抗热疲劳的能力增强,而WC颗粒使复合材料的传热系数降低是影响热疲劳性能的主要原因。 相似文献
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The thermal fatigue cracking behavior of high Si-Mo nodular cast iron (NCI) is investigated by means of optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectroscope (EDS), in order to find a new material used in exhaust manifolds in First Automotive Works (FAW). Nodular cast irons with silicon content about 4. 7%, in combination with up to 1. 1% molybdenum, were produced by Jilin University and FAW. The repeated heating/cooling test was performed under cyclic heating at various maximum heating temperatures (Tmax) ranging from 800 to 900 ℃. Experimental results indicate that the thermal fatigue cracking resistance of high Si-Mo NCI decreases with increasing the maximum heating temperature. The periods for crack initiation are 24-36, 40-50 and 70-90 times associated with heating temperature of 900, 850 and 800 ℃, respectively, when the holding time is about 10 min at Tmax. When thermal fatigue cracking occurs, the cracking always initiates at the bigger surface of specimen. The major positions of cracks propagation are generally at the eutectic oxide boundary region and the region of the graphite disappearance. At the same time, the oxidation may accelerate crack initiation and propagation. On the other hand, micro-crack number varied from large to little because of shielding effect. As exhaust manifolds, the reasonable working temperature of high Si-Mo NCI is no more than 840 ℃ by test and analysis. 相似文献
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Kyle E. Yazzie Jonathan Topliff Nikhilesh Chawla 《Metallurgical and Materials Transactions A》2012,43(10):3442-3446
When solder interconnects are fabricated, a Sn-based alloy is melted between two substrates with metallization layers, such as Cu or Ni. From the reaction between Sn and Cu, a Cu6Sn5 intermetallic compound (IMC) layer is formed at the solder/Cu interfaces. The morphology of the IMC layer greatly influences the mechanical behavior of the solder joint. Here, we report on the characterization of a novel, asymmetric growth behavior of IMC layers in Sn-3.9Ag-0.7Cu solder joints, based on gravity-induced spalling of the IMC. 相似文献
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Mustafa Demir Sezen Aksöz Esra Öztürk Necmettin Maraşlı 《Metallurgical and Materials Transactions B》2014,45(5):1739-1749
The variations of thermal conductivity with temperature in the Sn-based lead-free binary solders, Sn-10 wt pct X (X = Ag, In, Bi, Cu, Sb, Zn), were measured by using the linear heat flow apparatus. The thermal conductivities of Sn-based lead-free solders at their melting temperature were obtained from graphs of thermal conductivity variation with temperature. The variations of electrical conductivity with temperature for same solders were also determined from the Wiedemann–Franz (W–F) equation by using the measured values of thermal conductivity. 相似文献
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Oh Hojun Kim Jung Gi Lee Junmin Kim Sangshik 《Metallurgical and Materials Transactions A》2022,53(10):3604-3614
Metallurgical and Materials Transactions A - Environment-assisted fatigue crack propagation (EAFCP) behavior of as-built and β-annealed Ti64 specimens manufactured by direct energy deposition... 相似文献
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The thermal fatigue behavior of wear resistance cast iron with different quantity of deformation has been investigated. The results show that eutectic carbide is the main location and passage for initiation and extension of thermal fatigue cracks, approving that the more serious, the carbide breaks. The higher thermal fatigue resistance of wear resistance cast iron will be and thermal fatigue fracture belongs mainly to brittleness. 相似文献
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Massimo Pellizzari Daniel Massignani Sasan Amirabdollahian Faraz Deirmina 《国际钢铁研究》2023,94(4):2200449
Direct laser metal deposition (DLMD) is an additive manufacturing technique getting growing attention thanks to the possibility of producing very complex parts in a short time and in a cost-effective manner. The possible applications of this technology are tools with conformal cooling channels and claddings for dies and molds reparation. One of the damaging mechanisms of tools is thermal fatigue (TF) cracking, leading to surface deterioration and, consequently, the processed parts. Herein, the TF behavior of DLMD-H13 submitted to two different heat treatments, namely direct tempering (T) and quenching and tempering (QT), is investigated. T does not significantly change the solidification microstructure after DLMD, whereas QT produces a more homogenous tempered martensite microstructure. A customary laboratory test is developed to induce TF damage under a cyclic temperature variation between 630 and 60 °C. The results evidence that the T-H13 has a slightly better TF resistance with respect to QT-H13 due to the higher tempering resistance of T-H13 with respect to QT-H13. Thus, according to TF test results, direct tempering can be preferred to quench and tempering since the elimination of quenching can decrease the costs of production as well as distortions-related issues, increasing the competitiveness of DLMD. 相似文献
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开发的新型挤压轮用钢4Cr3.75MoSiV(/%:0.39C、0.95Si、0.35Mn、3.75Cr、1.25Mo、0.99V、0.009 5N)和常用挤压轮钢4Cr5MoSiV(/%:0.42C、1.20Si、0.38Mn、5.04Cr、1.14Mo、0.85V、0.035 0N)由10 kg真空感应炉熔炼,并锻成Φ18 mm试验用棒材,然后经880℃1 h+720℃1 h球化退火,1 080℃15 min油淬,550℃2 h+530℃2 h两次回火处理。研究了两种钢主要析出碳化物形貌、尺寸,析出比例和分布以及对500次600℃-室温连续热疲劳性能的影响。结果表明,含5.04%Cr的4Cr5MoSiV常用钢的析出物中V4C3+VC占12%,并有26%Cr23C6析出,而开发的4Cr3.75MoSiV新型钢中有利于提高热疲劳性能的析出物V4C3+VC占31%,未发现Cr33C6析出物;4Cr5MoSiV钢热疲劳损伤因子3.18×10-3,连续热疲劳试验表面裂纹比热疲劳损伤因子为1.77×10-3的新型4Cr3.75MoSiV钢表面裂纹粗大。 相似文献
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While composite-reinforced glulam beams have been used in several bridge demonstration projects, knowledge of their fatigue behavior is quite limited. In this study, the response of full- and partial-length fiberglass composite-reinforced glulam beams under fatigue cycling followed by quasi-static bending to failure is examined. To mimic anticipated in-service conditions, a hygrothermal cycling regime was developed that replicates the effective stress history of a 50-year service life with a 55-day period in a moisture-controlled kiln. In addition, some of the beams had initial delaminations introduced between the reinforcing and the wood similar to those observed in field investigations of reinforced glulam bridge girders. For the partial-length reinforced beams, reinforcing with both confined and unconfined ends was considered. The results of the postfatigue tests to failure were compared with the expected strength. In addition, the stiffness of the beams was monitored during the fatigue cycling. It was found that, with the exception of the unconfined, partial-length reinforced beams, all specimens had a residual strength that compared favorably with the expected strength. Further, neither the preconditioning nor the fatigue cycling had an appreciable impact on the stiffness of the reinforced beams. The unconfined, partial-length reinforced beams did not perform well under fatigue loading and do not seem to be a viable alternative for use as reinforced glulam bridge girders. 相似文献
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The uniaxial fully reversed (R?=??C1) long life fatigue behavior of four shot-peened engineering steels with approximately the same hardness was investigated. Shot-peening, air-cooled forged AISI 1141 and crackable AISI 1070 steels had little effect on their fatigue limits (+2.5 and ??C2.0?pct, respectively). In the case of a powder forged 0.5?pct C steel, an increase in the fatigue limit of 10.4?pct was observed, albeit with a large standard deviation. Shot-peening quench and tempered AISI 1151 steel decreased its fatigue limit 12.0?pct, as a result of cyclic softening. In general, the beneficial effects of shot-peening these smooth specimens were relatively small. Neither cyclic softening nor hardening occurred in the non?Cshot-peened steels cycled under the same conditions. 相似文献
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To date, research on concrete-filled fiber-reinforced polymer (FRP) tubes (CFFT) has focused on the effect of static loads, simulated seismic loads, and long-term sustained loads. Dynamic fatigue behavior of CFFTs, on the other hand, has received little or no attention. This paper reports on an experimental study to evaluate damage accumulation, stiffness degradation, fatigue life, and residual bending strength of CFFT beams. A total of eight CFFT beams with four different types of FRP tube were tested under four point bending. Test parameters included reinforcement index, fiber architecture, load range, and end restraints. Fatigue performance of CFFT beams is clearly governed by characteristics of the FRP tube and its three phases of damage growth: matrix cracking, matrix delamination, and fiber rupture. Lower reinforcement index increases stiffness degradation and damage growth, and shortens fatigue life. End restraints, e.g., embedment of FRP tube in adjacent members, promote composite action, arrest slippage of concrete core, and enhance fatigue life of CFFT beams. It is suggested that a maximum load level of 25% of the static capacity be imposed for fatigue design of CFFTs. With proper design, CFFTs may withstand repeated traffic loading necessary for bridge girders. 相似文献
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研究了激光熔覆和Ni-Al合金涂层及(Ni-Al)+WC复合涂层的热疲劳性能。结果表明,涂层疲劳损伤形式为沿晶应力(氧化)腐蚀。腐蚀产物为Al2O3。每次热循环后,熔覆层中的最终残余应力是残余热应力和相变应力共同作用的结果。由于复合涂层中的残余应力为压应力,而合金涂层中的残余应力为拉应力,因此前热疲劳性能优于后者。 相似文献