Brazing of 5A01 aluminum alloy using Al-Cu-Si-Ni filler metal

The vacuum brazing of 5 A01 aluminum alloy using Al-Cu-Si-Ni filler metal was investigated at 550 ℃ and 560 ℃,respectively. Microstructure and properties of brazed 5 A01 alloy joints were investigated by tensile-shear tests and scanning electron microscopy analysis. The effects of brazing temperature and holding time on the shear strength and microstructure of the joints were studied. The results show that the different intermetallic compounds such as Al-Cu-Ni and Mg_2 Si formed in the bonding area. Shear strength increased with holding time and brazing temperature. The average shear strengths increased from 42. 3 MPa brazed at 550 ℃for 5 min to 68 MPa brazed at 560 ℃ for 15 min. Discontinuous cracks were found in the joint brazed at 550 ℃ for 5 min,and the joint showed poor shear strength. high shear strength were obtained in the joints brazed at 560 ℃ for 15 min.     

Effect of parameters on interface of the brazed ZrO2 ceramic and Ti-6Al-4V joint using Ti-based amorphous filler

A commercially available Ti47 Zr28 Cu14 Ni11 (at. pct) amorphous filler foil was used to join ZrO2 ceramic and Ti-6Al-4V alloy. According to experimental observations, the interface microstructure accounts for the mechanical properties of the joints. The effects of brazing conditions and parameters on the joint properties were investigated. The joint shear strength showed the highest value of about 108 MPa and did not monotonously increase with the brazing time increasing. It was shown that decreasing of brazing cooling rate and appropriate filler foil thickness gave higher joint strength.     

Microstructure characteristics and mechanical properties of steel stud to Al alloy by CMT welding-brazing process

Cold metal transfer(CMT) welding of nickel-coated Q235 steel studs with 6061 Al alloy was carried out using ER4043 as filler metal.The welding process was stable,and appearance of weld formed well without surface defect under the parameters of welding current 121 A,welding voltage 15.4 V and welding speed 6 r/min.The microstructure of filler metal was analyzed by means of scanning electron microscopy.The filler metal and 6061 Al alloy were fused to form fusion welding interface,the fusion zone had a good bonding without any micro defect.The steel stud did not melt and brazing interface was formed between the filler metal and steel stud.Two different reaction layers existed in the brazing interface,the Fe_2Al_5 layer about 10- 12 μm formed near the steel stud side,and the other layer was mainly composed of FeAl_3.Nickel-rich zone was formed in the root toe area of the fillet weld,which was mainly composed of Al_3Ni_2.The tensile tests showed that the maximum shearing strength of the joints was 129 MPa.The joint was brittle fractured in the intermetallic compound layer where plenty of FeAl_3 were distributed continuously.     

Effect of bonding parameters on microstructure and properties of Si3S4／Si3S4 joint brazed by Cu-Zn-Ti filler alloy

Si3N4 ceramic was jointed to Si3N4 ceramic using a filler alloy of Cu-Zn-Ti at 1 123-1 323 K for 0.3- 2.7 ks. Ti content in the Cu-Zn-Ti filler alloy was 15% (molar fraction). The effect of bonding parameters on the microstructure and mechanical properties of the Si3N4/Si3N4 joint were investigated. The results indicate that with increasing brazing temperature from 1 123K to 1 323 K and brazing time from 0.3 ks to 2.7 ks, the thickness of the interracial reaction layer between the filler alloy and the Si3 N4 ceramic and the size and amount of the reactant products in the filler alloy increase, leading to an increase in shear strength of the joint from 163 MPa to 276 MPa. It is also found that the fracture behavior of the Si3 N4/Si3 N4 joint greatly depends on the microstructure of the joint.     

Influence of holding time on microstructure and shear strength of Mg alloy/steel joint diffusion bonded with Zn－5Al interlayer

The diffusion bonding of AZ31B Mg alloy and Q235 steel was investigated with a Zn-5Al alloy as interlayer and under different holding time ranging from 3 to 1 200 s.The microstructure and phase compositions of bonded joints were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) methods.The shear strength of Mg alloy/steel joints was measured by tensile tester.It was found that the microstructure of bonded joints evolved dramatically along with the prolongation of holding time.Under the holding time of 3 s, the main part of joint was composed of MgZn2 phase and dispersed Al-rich solid solution particles.When increased the holding time more than 60 s, the excessive solution of AZ31B into the interfacial reaction area led to the formation of coarse phase and eutectic microstructure, and also the complex Fe-Al and Mg-Al-Zn IMCs at transition layer closed to Q235 steel side.According to the tensile testing characterizations, the joints obtained under holding time of 3 s exhibited the best shear strength of 84 MPa, and the fracture occurred at the intermediary part of joint where the flexible Al-rich solid solution particles could help to impede the microcrack propagations.With prolonging the holding time to 600 s, the shear strength of joints was deteriorated enormously and the fracture position was shifted to the transition layer part closed to Q235 steel.     

Effects of Joining Conditions on Microstructure and Mechanical Properties of C_f/Al Composites and TiAl Alloy Combustion Synthesis Joints

Cf/Al composites and TiAl alloy were joined by combustion synthesis in different joining conditions.Effects of additive Cu,joining temperature and holding time on joint microstructure and shear strength were characterized by employing DTA,SEM,EDS,XRD and shear test.Results show that the additive Cu in the Ti–Al–C interlayer could significantly decrease the reaction temperature owing to the emergence of Al–Cu eutectic liquid.Reaction degree of the interlayer was influenced by joining temperature and holding time.Due to the barrier action of formed TiAl3 layer,reaction rate of Ti and Al was determined by the atoms diffusion.The reaction between Ti and Al was more sensitive to the joining temperature rather the holding time.The joints shear strength was influenced by joining condition directly.The maximum shear strength of CS joints was 25.89 MPa at 600 °C for 30 min under 5 MPa.Interface evolution mechanism of the CS joint was analyzed based on the experimental results and phase diagram.     

Study on vacuum brazing of Cf/C composites

Vacuum brazing experiments of Cf/C composites were carried out using pure Al and Al-5 Ti-B as brazing fillers , and shearing strength of the joints was measured. The microstructures of the brazed joints were studied by means of scanning electron microscopy （SEM） and energy dispersive X-ray spectrometer. The results indicate that the brazing temperature is the important processing parameter affecting the quality of the brazed joints. Vacuum brazing of Cf/C composites can be achieved employing the pure Al and AI-S Ti-B brazing fillers at a brazing temperature of 730 ℃ or 750 ℃ , respectively. Moreover, the joints have excellent microstructures with shear strength reaching the level of practical applications.     

New approaches for brazing temperature sensitive materials

PVD deposited copper interlayers as filler materials were used in order to manufacture TLP brazed magnesium joints. The microstructure and interface characteristics of the overlap joints were investigated by optical microscopy, scanning electron microscope with energy dispersive spectrometer and tensile testing. Sound brazed joints could be achieved. The dwell time is the main factor to control the thickness of the reaction layer. It was shown that the deposited copper filler metal clearly reacted with the magnesium substrate , resulting in the formation of a magnesium solid solution （Mg） with different amount of copper, aluminum and zinc as well as Mg2Cu phases. With the progressing diffusion, the formation of intermetaUic compounds was suppressed and the hardness distribution in the brazing seam homogenized. The joints fractured at the interface, and the maximum average tensile shear strength of overlap joints reached 85 MPa.     

EFFECT OF BRAZING TIME ON TiC CERMET／IRON JOINT BRAZED WITH Ag-Cu-Zn FILLER METAL

The brazing of TiC cermet to iron was carried out at 1223K for 5-20min using Ag-Cu-Zn filler metal.The formation phase and interface structure of the joints were investigated by electron probe microanalysis(EPMA).scanning electron microscopy(SEM) and X-ray diffraction(XRD).and the joint strength was tested by shearing method.The results showed:there occurred three new formation phases,Cu(s.s),FeNi and Ag(s.s) in TiC cermet/iron joint.The interface structure was expressed as TiC cermet/Cu(s.s) FeNi(Ag(s.s) a little Cu(s.s) a little FeNi/Cu(s.s) FeNi/iron.With brazing time increasing,there appeared highest shear strength of the joints.the value of which was up to 252.2MPa when brazing time was 10min.     

Ultrasonic dissolution of brazing of 55% SiCp/A356 composites

The brazing of 55% SiCp/A356 (volume fraction) composites in air using Zn-Al alloy as a filler metal was investigated.During the brazing process,ultrasonic vibrations were applied to samples for bonding and a significant dissolution of the filler metal into the matrix alloy in the base materials occurred.As brazing temperatures were increased,the thickness of the partial melting layers in the base material increased.SiC particles in the partial melting layer of the base material were transferred into the liquid filler under ultrasonic action and a bond with homogeneously distributed reinforcements was obtained after solidification.The volume fraction of SiC particles in the bonds could be varied by changing the brazing temperature.The maximum SiC particle volume fraction of the bond material reached 37% at a brazing temperature of 500 ℃.The shear strength of the brazed bonds was improved at pressures up to 244 MPa (at 20 ℃) and increased by 133.8% (at 200 ℃) compared with the filler of the Zn-based alloy.     

Interface structure and mechanical properties of Ti(C,N)-based cermet and 17-4PH stainless steel joint brazed with nickel-base filler metal BNi-2

The effects of brazing temperature on microstructure and bonding strength of vacuum brazed joints of Ti(C,N)-based cermet and 17-4 PH stainless steel, using filler metal BNi-2, were investigated. At a lower brazing temperature of 1050 °C, the distribution of melting point depressants (MPD) concentrated on the diffusion affected zone (DAZ) and the brazing seam near the Ti(C,N)-based cermet, the generation of brittle phases in the brazing seam was unavoidable. The uniform distribution of the MPD and full solid solution of γ-nickel occurred in the brazing seam at a higher brazing temperature of 1150 °C. A maximum shear strength of 690 MPa was achieved at a brazing temperature of 1150 °C.     

Si3N4/AgCu/TiAl钎焊接头界面结构及性能

采用AgCu非活性钎料实现了Si3N4陶瓷与TiAl基合金的钎焊,确定接头的典型界面组织结构为:TiAl/Ti3Al+Ti(s,s)/AlCuTi/Ag(s,s)+AlCu2Ti/Ti5Si3+TiN/Si3N4陶瓷。钎焊过程中,活性元素Ti从TiAl母材溶解到钎料中与Si3N4陶瓷发生反应润湿,实现了TiAl与Si3N4陶瓷的连接。随着钎焊温度的升高及保温时间的延长,靠近Si3N4陶瓷的TiN反应层厚度增加,Ag基固溶体中弥散分布的AlCu2Ti化合物聚集长大成块状,导致接头性能下降。当钎焊温度T=860℃,保温时间为5min时接头抗剪强度达到最大值124.6MPa。基于反应热力学及动力学计算TiN层反应激活能Q约为528.7kJ/mol,860℃时该层的成长系数KP=2.7×10-7m/s1/2。     

Invar合金与Si_3N_4陶瓷钎焊接头界面组织和性能研究

采用Ag Cu Ti活性钎料对Invar合金和Si3N4陶瓷进行钎焊连接,研究了接头界面组织及其形成机制,分析了钎焊工艺参数对接头界面结构和性能的影响。结果表明,钎焊过程中液态钎料中的活性元素Ti与Si3N4陶瓷发生反应,在陶瓷界面形成致密的Ti N和Ti5Si3反应层;同时,Invar合金向液态钎料中溶解,与活性元素Ti反应生成脆性的Fe2Ti和Ni3Ti化合物。钎焊温度和保温时间影响Si3N4陶瓷界面反应层的厚度以及接头中Fe2Ti和Ni3Ti脆性化合物的形成量和分布,这两方面共同决定着接头的抗剪强度。当钎焊温度为870℃,保温15 min时,接头的平均抗剪强度最大值达到92.8 MPa,此时接头的断裂形式呈现沿Si3N4陶瓷基体和界面反应层的复合断裂模式。     

5005铝合金与1Cr18Ni9Ti的真空钎焊分析

采用Al-Si-Mg钎料成功实现了5005铝合金与1Cr18Ni9Ti不锈钢的真空钎焊,借助扫描电镜、能谱分析仪和X射线衍射仪对焊后接头界面组织进行分析,同时对接头抗剪强度进行测试.结果表明,焊后接头界面结构从1Cr18Ni9Ti不锈钢侧到5005铝合金侧的界面组织依次为FeAl,FeAl₃,Fe_mAl_n+αAl.随着钎焊温度的升高或保温时间的延长,接头抗剪强度均呈现先升高后降低的变化趋势.当钎焊温度为580℃,保温时间为15 min时,接头抗剪强度达到最大值49 MPa.接头断裂形式受钎焊温度的影响,当钎焊温度较低时,接头断裂于铝合金侧氧化膜层及Fe_mAl_n+αAl反应层;温度升高至580℃时,接头断裂于Fe_mAl_n+αAl反应层中,接头抗剪强度最高.     

Ti(C,N)基金属陶瓷与45钢感应钎焊的界面结构及强度

采用AgCuZn钎料实现了Ti(C,N)基金属陶瓷与45钢的高频感应钎焊连接。研究了钎焊温度对感应钎焊接头强度的影响,在本试验中,当钎焊温度为900℃时得到的接头界面强度达到最大值,其剪切强度和抗弯强度分别达到133.7 MPa和91.2 MPa。利用SEM、EDS、XRD等微观分析手段,研究了钎焊界面的微观结构,感应钎焊接头的反应产物45钢侧主要为Ag基固溶体和Cu0.64Zn0.36金属间化合物;在金属陶瓷侧,主要为Ag基和Cu基固溶体。     

TC4/Ti60合金钎焊接头界面组织及力学性能

采用TiZrNiCu非晶钎料实现了TC4和Ti60异种钛合金的真空钎焊连接,利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等分析手段研究了钎焊工艺参数对接头界面组织结构及力学性能的影响. 结果表明,TC4/TiZrNiCu/Ti60钎焊接头的典型界面结构为:TC4/α-Ti+β-Ti+(Ti,Zr)2(Ni,Cu)/Ti60. 随着钎焊温度升高或保温时间延长,片层状α+β相逐渐填充整条钎缝,(Ti,Zr)2(Ni,Cu)相含量减少且分布更加均匀. 接头室温抗拉强度随钎焊温度或保温时间的增加均先增大后减小,在990 ℃/10 min钎焊条件下所获接头抗拉强度达到最大为535.3 MPa. 断口分析结果表明,断裂位于钎缝中,断裂方式为脆性断裂.     

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.     

Preliminary Investigation on Brazing Performance of Ti/Ti and Ti/Steel Joints Using Copper Film Deposited by PVD Technique

Microstructural aspects and bonding characteristics of vacuum brazed Ti/Ti and Ti/steel were investigated. A thin-copper film, with different thicknesses, was deposited on the brazed metals by physical vapor deposition technique to serve as a brazing filler metal. Test joints were processed at a temperature of 910 °C and 15 min holding time. The resultant joints were characterized to determine the brittle intermetallic compound in the interfacial layer and the shear strength of the joints were tested. Our preliminary experimental results showed that sound joints with a good wetting quality, lack of pores and cracks can be achieved. Intermetallic phases such as Ti₂Cu, TiCu, FeTi, and Fe₂Ti were predicted from the chemical analyses. The Ti/Ti joints achieved a higher shear strength than the Ti/steel joints and there is a tendency for the tension shear strength to increase when a thick Cu-deposited layer is used.     

采用Cu-Ti钎料高温连接Si3N4陶瓷

采用Cu80Ti20钎料在1413~1493 K的温度,保温时间5~15 min的工艺条件下分别进行了Si₃N₄陶瓷的高温活性钎焊,在所选工艺条件下均成功得到了无明显缺陷和裂纹的钎焊接头,通过对接头组织和成分的分析,接头的组成为Si₃N₄陶瓷/TiN界面反应层/Cu-Ti化合物+Ti5Si3/TiN界面反应层/Si₃N₄陶瓷.在1413 K保温10min条件下,固溶体中的Ti元素扩散至钎缝与母材的界面并发生反应,形成了致密连续的厚度约为1 μm的反应层.获得了钎焊温度、保温时间、钎缝宽度及界面层厚度等对接头强度的影响规律,在试验中所采用的工艺参数条件下,接头抗剪强度达到了105 MPa.     

工艺参数对Al2O3/TC4合金接头界面组织及力学性能的影响

采用Cu＋B钎料分别在钎焊温度890～970℃,保温时间为10min;钎焊温度为930℃,保温时间0～30min条件下,钎焊A120,陶瓷与TCA合金．利用SEM,EDS和压剪试验研究接头界面组织及力学性能．结果表明,随钎焊温度升高或保温时间的延长,Ti2（Cu,Al）2O层增厚,紧邻其侧生成连续并增厚的Ti2（Cu,Al）,Ti2（Cu,Al）含量增加;Ti＋Ti2（Cu,Al）含量增加,尺寸变大,分布范围逐渐变宽并向TC4合金侧迁移,TCA合金侧过共析组织区变宽．钎焊温度低于950℃时,TiB晶须主要分布在Ti2Cu晶界处的AlCu2Ti上;当钎焊温度高于950℃时,AlCu2Ti相逐渐消失,TiB晶须主要分布于Ti2Cu上．当保温时间为10min,钎焊温度为950℃时,接头最大强度为96MPa;而当钎焊温度为930℃,保温时间为20min时,接头最大强度为83MPa．关键词：Al2O3陶瓷;TC4合金;钎焊参数;界面组织;抗剪强度