Numerical simulation of copper based filler metal droplets spreading under arc brazing

1 INTRODUCTION Arc brazing technology is a newly developed joining technology .For its advantages ,it has been used more and more frequently in automobile industry and other wiring equipments . And this technology is considered to have a big foreground in practical joining applications . But up to now, the studies of this technology are restrained in practical production applications[1 3]and experi- mental analyses[4 ,5]; and few researchers have studied the spreading of liquid droplets ,…     

Brazing of A5056 aluminium alloy with the aid of ultrasonic vibration using Ag filler metal

In order to produce a high strength brazed joint of A5056 aluminium alloy containing magnesium of about 5 mass%, the authors applied a flux-free brazing method with the aid of ultrasonic vibration to the aluminium alloy by selecting pure Ag foil as brazing filler metal and examined the effect of brazing conditions on the joint properties. The main results obtained in this study are as follows.

At a brazing temperature of 570°C, just above the eutectic point of Al–Ag binary system, application of ultrasonic vibration for 4.0 s provided the brazed joint with the maximum tensile strength and the strength decreased with the application time. When the brazing temperature was varied from 550 to 580°C and the application time of ultrasonic vibration was kept constant at 4.0 s, the joint brazed at 560°C attained the maximum tensile strength and fractured in the base metal. It was found that using a pure Ag foil as brazing filler metal successfully brazed A5056 aluminium alloy and the joint strength was equivalent to that of the base metal. Fracture of the joint was prone to occur along the (Al₃Mg₂ + Al solid solution) phase with high hardness formed at the grain boundary of the base metal. The amount of the hard (Al₃Mg₂ + Al solid solution) phase increased with the ultrasonic application time and the brazing temperature. It seemed that the increase of the hard (Al₃Mg₂ + Al solid solution) phase mainly caused the brazed joint strength to decrease.     

AgCuZnMnNi钎料感应钎焊35CMo/YG15C焊缝强度研究

根据该银基钎料的可焊接温度制定钎焊温度,每次试验试样的位置相同,利用高频感应钎焊进行焊接.制定焊接温度为630℃、650℃、670℃、700℃,保温时间30s.试验结果表明,放置在感应圈相同位置,保温时间相同的情况情况下,随着焊接温度的升高,抗剪强度呈现先增大后减小的趋势.在670℃达到最大,为388 MPa.焊缝缺陷主要为夹渣和气孔,未出现未焊透、裂纹等缺陷.     

新型锌基复合钎料的制备及性能

采用电镀技术制备新型复合锌基钎料,借助于差热分析(DTA)、X射线衍射(XRD)等手段对钎料的性能进行分析。分析结果表明:新型复合钎料熔点与普通钎料相比,略高于普通钎料;同一钎焊条件下,新型复合钎料润湿性优于普通钎料,且其钎焊接头的强度高于普通钎料。     

铝基复合材料用Al-12Si-xTi系三元活性钎料的制备(英文)

为了改善常用钎料对铝基复合材料的润湿性,制备了新型Al-12Si-xTi系三元活性钎料。研究表明,所添加的Ti以Ti(Al1-xSix)3(0≤x≤0.15)相存在,但由于钎料的主要组织均为Al-Si共晶组织,所以Al-12Si-xTi钎料与传统Al-12Si钎料具有相似的剪切强度和剪切断口。因此,加入少量Ti(～1%)不会使钎料脆化和硬化;而且Al-12Si-xTi钎料带的成分接近共晶成分,所以熔化区间非常相似,为580～590℃。对于润湿性的改善,是由于随着钎料中Ti含量的增加,Al2O3增强相和钎料金属间的(R/M)界面间隙得到消除的原因。润湿实验后在铝基复合材料表面残留的钎料量也随着钎料含Ti量的增加而减少。因此,Ti对于润湿性的改善可以随着钎料含Ti量的增加而较为容易地被重复观察到。此外,Ti(AlSi)3的量和尺寸对含Ti量(焊接前)和含Si量(焊接后)敏感。     

Low-melting-point titanium-base brazing alloys—part 1: Characteristics of two-, three-, and four-component filler metals

The melting point, microstructure, phase, and electrochemical behavior of Ti-21Ni-15Cu alloy, together with two-, three-, and four-component low-melting-point titanium-base brazing alloys, are presented in this paper. Five filler metals were selected for the study, in which melting points were measured by differential thermal analysis, phases identified by x-ray diffractometry, and corrosion behaviors tested by potentiodynamic polarization. The experimental results show that the three-component Ti-15Cu-15Ni and the newly developed Ti-21Ni-14Cu alloys exhibit the combination of lower melting point and superior corrosion resistance compared to the two-and four-component titanium alloys, 316L stainless steel, and a Co-Cr-Mo alloy in Hank’s solution at 37 °C. On a short time basis, the presence of Ti₂Ni and Ti₂Cu intermetallics in the Ti-15Cu-15Ni and Ti-21Ni-14Cu alloys should not be preferentially dissolved in galvanic corrosion with respect to the dissimilar Ti-6Al-4V alloy.     

Strength and interfacial microstructure of Si3N4 joint brazed with amorphous Ti-Zr-Ni-Cu filler metal

In this paper, the vacuum brazing of Si3N4 ceramic was carried oat with Ti40Zr25Ni15Cu20 amorphous filler metal. The interfacial microstructure was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) etc. According to the analysis, the interface reaction layer was made up of TiN abut on the ceramic and the Ti-Si, Zr-Si compounds. The influence of brazing temperature and holding time on the joint strength was also studied. The results shows that the joint strength first increased and then decreased with the increasing of halding time and brazing temperature. The joint strength was significantly affected by the thickness of the reaction layer. Under the same experimental conditions, the joint brazed with amorphous filler metal exhibits much higher strength compared with the one brazed with crystalline filler metal with the same composition. To achieve higher joint strength at relatively low temperature, it is favorable to use the amorphous filler metal than the crystalline filler metal.