DD3高温合金与Ti3AlC2陶瓷的真空钎焊

通过对比试验优选出了合适钎料,并进行了后续钎焊试验.在钎焊温度800~900℃,保温时间为10 min的条件下,采用Ag-Cu-Ti钎料实现了DD3镍基高温合金与Ti₃AlC₂陶瓷的真空钎焊连接.利用扫描电镜、能谱仪、XRD等对接头的界面结构进行了分析.结果表明,接头的典型界面结构为DD3/AlNi/Al₃(Ni,Cu)₅+Al(Ni,Cu)+Ag_ss/(Al,Ti)₃(Ni,Cu)₅/Al₄Cu₉+AlNi₂Ti+Ag_ss/TiAg/Ti₃AlC₂.接头的力学性能测试表明,在钎焊温度为850℃,保温时间为10 min的条件下,接头的最高抗剪强度可达135.9 MPa,断裂发生在靠近钎缝的Ti₃AlC₂陶瓷侧.降低和提高钎焊温度对接头界面组织影响不大,但接头强度有一定程度下降.     

Ag-Cu+WC复合钎料钎焊ZrO2陶瓷和TC4合金

采用新型Ag-Cu+WC复合钎料进行ZrO₂陶瓷和TC4合金钎焊连接,探究了接头界面组织及形成机制,分析了钎焊温度对接头界面结构和力学性能的影响. 结果表明,接头界面典型结构为ZrO₂/TiO+Cu₃Ti₃O/TiCu+TiC+W+Ag_(s,s)+Cu_(s,s)/TiCu₂/TiCu/Ti₂Cu/TC4. 钎焊过程中,WC颗粒与Ti发生反应,原位生成TiC和W增强相,为Ti-Cu金属间化合物、Ag基和Cu基固溶体提供了形核质点,同时抑制了脆性Ti-Cu金属间化合物的生长,优化了接头的微观组织和力学性能. 随钎焊温度的升高,接头反应层的厚度逐渐增加,WC颗粒与Ti的反应程度增强. 当钎焊温度890 ℃、保温10 min时,复合钎料所得接头抗剪强度达到最高值82.1 MPa,对比Ag-Cu钎料所得接头抗剪强度提高了57.3%.     

SiCP/Al复合材料的真空扩散钎焊

文中采用Al/Cu/Al复合箔扩散钎焊SiC_P/Al复合材料,采用SEM,EDS,XRD分析接头界面组织,研究了钎焊温度对接头界面组织及力学性能的影响,并结合Al-Cu二元相图分析接头形成机制.结果表明,固定连接压力为1 MPa,保温时间为10 min,当钎焊温度从590℃升至640℃,接头界面产物由Al₂Cu+αAl共晶组织转变为断续的Al₂Cu金属间化合物,Al-Cu液相向两侧母材扩散的距离增加,接头的抗剪强度呈现先增大后减小的变化趋势.当钎焊温度为620℃,保温时间为10 min,连接压力为1 MPa时,接头的抗剪强度达到最大值69 MPa.     

Cf/LAS复合材料的钎焊接头组织与性能分析

采用Ag-Cu-Ti活性钎料对C_f/LAS复合材料进行了钎焊,研究了接头界面组织结构和力学性能.采用扫描电子显微镜（SEM）、能谱仪（EDS）和X射线衍射（XRD）对钎焊接头组织结构进行分析,用抗剪试验检测接头力学性能.结果表明,接头界面典型结构为C_f/LAS复合材料/TiSi₂/Cu₂Ti₄O/TiCu/Ag（s,s）+Cu（s,s）/TiCu/Cu₂Ti₄O/TiSi₂/C_f/LAS复合材料.在钎焊温度为900℃,保温时间为10 min时,接头室温抗剪强度最高达8.4 MPa.     

表面活化Al2O3陶瓷与5005铝合金真空钎焊

采用Al-Si钎料对经过Ag-Cu-Ti粉末活性金属化处理的Al₂O₃陶瓷与5005铝合金进行了真空钎焊,研究了钎焊接头的典型界面组织,分析了钎焊温度对接头界面结构特征及力学性能的影响. 结果表明,接头典型界面结构为5005铝合金/α-Al+θ-Al₂Cu+ξ-Ag₂Al/ξ-Ag₂Al+θ-Al₂Cu+Al₃Ti/Ti₃Cu₃O/Al₂O₃陶瓷. 钎焊过程中,Al-Si钎料与活性元素Ti及铝合金母材发生冶金反应,实现对两侧母材的连接. 随着钎焊温度的升高,陶瓷侧Ti₃Cu₃O活化反应层的厚度逐渐变薄,溶解进钎缝中的Ag和Cu与Al反应加剧,生成ξ-Ag₂Al+θ-Al₂Cu金属间化合物的数量增多,铝合金的晶间渗入明显;随钎焊温度的升高,接头抗剪强度先增加后降低,当钎焊温度为610 ℃时,接头强度最高达到15 MPa.     

Ni-P镀层对Cu/Al钎焊界面结构及性能的影响机制

为了研究Ni-P镀层对Cu/Al异种金属钎焊界面反应的影响,首次采用Zn98Al和BAl67CuSi两种钎料对含/不含Ni-P镀层的T2紫铜与3003铝合金进行了高频钎焊,获得4种不同的钎焊接头,分别对接头Cu侧界面结构、抗剪强度、断口形貌、显微硬度及弯曲形貌进行了系统研究,并与无镀层接头进行对比. 结果表明,T2表面镀覆Ni-P后,Cu/Zn98Al/Al接头中Cu基体/钎缝界面结构由扩散层+8.8 μm厚的Cu_3.2Zn_4.2Al_0.7化合物转变为1.5 μm厚的Al₃Ni化合物,而Cu/BAl67CuSi/Al接头中Cu基体/钎缝界面结构由扩散层+15 μm厚CuAl₂转变为1.8 μm厚Cu₃NiAl₆;与无镀层接头相比,镀覆Ni-P后,Cu/Zn98Al/Al接头强度略有上升,Cu/BAl67CuSi/Al接头强度略有下降,但两种接头的韧性均明显增强,力学性能试验结果与接头Cu侧界面微观组织转变规律相符. 最后建立了Cu/Al接头的界面反应模型,并阐明了Ni-P镀层对Cu/Al接头界面结构和力学性能的影响机制.     

Ag-Cu钎料钎焊ZTA陶瓷与TC4钛合金

使用Ag-Cu钎料钎焊ZTA陶瓷与TC4钛合金,利用扫描电子显微镜(SEM)、能谱分析仪(EDS)和X射线衍射仪(XRD)等设备分析了钎焊接头界面组织,阐明了反应机理,并研究了钎焊温度对接头界面组织和力学性能的影响. 结果表明,钎焊接头的界面结构为ZTA陶瓷/TiO+Ti₃(Cu,Al)₃O/Ag(s,s)/Ti₂Cu₃/TiCu/Ti₂Cu/α+β-Ti/TC4合金. 随着钎焊温度的升高,钎缝中Ag基固溶体层变薄,Ti-Cu金属间化合物层变厚,当钎焊温度达到890 ℃时,Ti-Cu金属间化合物几乎占据整了个钎缝区域. 随着温度的升高,接头抗剪强度先增大后减小,在钎焊温度为890 ℃时,接头的室温抗剪强度达到最大值,其值为43.2 MPa.     

CNTs对TC4与C/C复合材料钎焊接头组织及力学性能的影响

试验采用加入了碳纳米管(carbon nanotubes,CNTs)的AgCu4.5Ti + xCNTs (x为质量分数,%)复合钎料(简称AgCuTi_C复合钎料),实现了TC4钛合金与C/C复合材料的真空钎焊连接. 通过SEM,EDS等分析手段确定了在CNTs含量为0.2%、钎焊温度为880 ℃、保温时间为20 min时接头的典型界面组织为TC4/扩散层/Ti₂Cu/TiCu/Ti₃Cu₄/TiCu₄/TiC + TiCu₂ + Ag(s.s) + Cu(s.s)/Ti₃Cu₄/TiCu₄/TiC/C/C复合材料;研究了CNTs含量对接头组织与性能的影响. 结果表明,随着CNTs含量的增加,钎缝宽度变化呈下降趋势,界面组织细化,界面中的Ti₃Cu₄与TiCu₄脆性化合物的含量降低、TiC与TiCu₂化合物的含量增加;接头的抗剪强度呈先上升后下降的趋势变化;当CNTs含量为0.4%时抗剪强度最高,达到44 MPa;CNTs的加入可使界面组织得到细化,有利于缓解钎缝中心区域与两侧母材之间存在的由于热膨胀系数不匹配而形成的较大残余应力,有效地提高了接头的抗剪强度.     

Cu-25Sn-10Ti活性钎焊SiO2f/SiO2复合材料与Invar合金

采用Cu-25Sn-10Ti钎料钎焊SiO_2f/SiO₂复合材料与Invar合金,研究了界面组织结构及其形成机理,分析了不同钎焊保温时间下界面组织对接头性能的影响.结果表明,在钎焊温度880℃,保温时间15 min的工艺参数下,接头在SiO_2f/SiO₂复合材料侧与Invar合金侧均形成了连续的界面反应层,界面整体结构为Invar合金/Fe₂Ti+Cu(s,s)+(Ni,Fe,Cu)₂TiSn/Cu(s,s)+Cu₄₁Sn₁₁+CuTi/TiSi+Ti₂O₃/SiO_2f/SiO₂复合材料.在钎焊温度一定时,随着保温时间的延长,复合材料侧TiSi+Ti₂O₃反应层厚度逐步增加,Fe₂Ti颗粒逐步呈大块状连续依附其上,接头强度先增大后减小.当钎焊温度880℃,保温时间15 min时,接头室温抗剪强度达到11.86 MPa.     

保温时间对铝/铜钎焊接头界面化合物和力学性能的影响

采用Zn-22Al钎料配合KAlF4-CsAlF4无腐蚀钎剂,在不同保温时间下对铝/铜进行炉中钎焊,研究了保温时间对钎焊接头、微观组织形貌,铜侧界面元素分布以及接头力学性能的影响.结果表明,随着保温时间的延长,Al/Cu接头Cu/钎缝界面CuAl₂化合物由层片状逐渐转变为树枝状并向钎缝内部生长;钎缝中的CuAl₂相由粗大块状转变为长条状或薄片状;Cu/钎缝界面处Zn元素含量峰值在保温时间为2 min时出现在铜母材与AlCu化合物之间,随着保温时间延长,Zn元素峰值逐渐向钎缝内部迁移.同时,铝/铜钎焊接头的抗剪强度随保温时间延长先提高后降低.     

Microstructure and mechanical properties of Cu/Al joints brazed using (Cu,Ni, Zr,Er)-modified Al—Si filler alloys

To design a promising Al—Si filler alloy with a relatively low melting-point, good strength and plasticity for the Cu/Al joint, the Cu, Ni, Zr and Er elements were innovatively added to modify the traditional Al—Si eutectic filler. The microstructure and mechanical properties of filler alloys and Cu/Al joints were investigated. The result indicated that the Al—Si—Ni—Cu filler alloys mainly consisted of Al(s,s), Al₂(Cu,Ni) and Si(s,s). The Al—10Si—2Ni—6Cu filler alloy exhibited relatively low solidus (521 °C) and liquidus (577 °C) temperature, good tensile strength (305.8 MPa) and fracture elongation (8.5%). The corresponding Cu/Al joint brazed using Al—10Si—2Ni—6Cu filler was mainly composed of Al₈(Mn,Fe)₂Si, Al₂(Cu,Ni)₃, Al(Cu,Ni), Al₂(Cu,Ni) and Al(s,s), yielding a shear strength of (90.3±10.7) MPa. The joint strength was further improved to (94.6±2.5) MPa when the joint was brazed using the Al—10Si—2Ni—6Cu—0.2Er—0.2Zr filler alloy. Consequently, the (Cu, Ni, Zr, Er)-modified Al—Si filler alloy was suitable for obtaining high-quality Cu/Al brazed joints.     

中间层对高体积分数SiCp/Al复合材料真空钎焊的影响

采用铜箔、Al-Si-Mg及Al-Si-Mg/Cu/Al-Si-Mg(简称ACA)3种不同中间层对高体积分数45%SiC_p/Al复合材料进行真空钎焊连接研究.通过SEM,EDS及XRD等方法对钎缝的微观结构及界面组织进行了分析,研究了中间层种类对钎焊接头微观结构、界面组织以及连接强度的影响,阐明了不同中间层钎焊连接45%SiC_p/Al复合材料的界面形成过程及接头断裂机制.结果表明,ACA中间层兼具了铜和Al-Si-Mg钎料的优点,可降低钎料的液相线,增加其流动性,通过Cu原子优先在铝合金基体与其氧化膜的界面处扩散发生共晶反应,增强钎料的去膜作用,从而实现高体积分数45%SiC_p/Al复合材料的高质量连接.     

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.     

Cu + TiB2 composite filler for brazing Al2O3 and Ti-6Al-4V alloy

Al₂O₃ and Ti-6Al-4V alloy were brazed using Cu + TiB₂ composite filler, which manufactured by mechanical milling of Cu and TiB₂ powders. Typical interface microstructure of joint was Al₂O₃/Ti₄(Cu,Al)₂O/Ti₂Cu + Ti₃Al + Ti₂(Cu,Al)/Ti₂(Cu,Al) + AlCu₂Ti/Ti₂Cu + AlCu₂Ti + Ti₃Al + Ti₂(Cu,Al) + TiB/Ti(s.s) + Ti₂Cu/Ti-6Al-4V alloy. Based on temperature- and time-dependent compositional change, the formation of intermetallics in joint was basically divided into four stages: formation of interfacial Ti₄(Cu,Al)₂O in Al₂O₃ side, formation of Ti₂Cu, Ti₃Al, TiB, Ti₂Cu, and AlCu₂Ti in layers II and IV, formation of Ti₂(Cu,Al) and AlCu₂Ti in layer III, formation of Ti + Ti₂Cu hypereutectoid organization adjacent to Ti-6Al-4V alloy. TiB in situ synthesized in joint not only acted as low thermal expansion coefficient reinforcement to improve the mechanical properties at room temperature, but also as skeleton ceramic of joint to increase high temperature mechanical properties of Al₂O₃/Ti-6Al-4V alloy joint increasing. When the joint containing 30 vol.% TiB brazed at 930 °C and 10 min of holding time, the maximum room temperature shear strength of joint was 96.76 MPa, and the high temperature shear strength of joint was 115.16 MPa at 800 °C.     

Infrared brazing of Ti–6Al–4V using two silver-based braze alloys

Infrared brazing of Ti–6Al–4V using two silver-based alloys is evaluated in the study. For the 72Ag–28Cu brazed specimen, Ag-rich matrix, eutectic Ag–Cu and Cu–Ti interfacial reaction layer(s) are observed in the experiment. In contrast, both Ag-rich matrix and interfacial titanium aluminides, TiAl or Ti₃Al, are found in the 95Ag–5Al brazed joint. In general, the shear strength of 72Ag–28Cu brazed joint is much higher than that of 95Ag–5Al brazed specimen. Additionally, the use of infrared brazing with lower brazing temperature and/or less time can significantly decrease both dissolution of the substrate into molten braze as well as excessive growth of the interfacial reaction layer(s) in the joint. Therefore, infrared brazing has the potential to be applied in industry.     

Brazing of TiBw/TC4 composite and Ti60 alloy using TiZrNiCu amorphous filler alloy

TiB_w/TC4 composite was brazed to Ti60 alloy successfully using TiZrNiCu amorphous filler alloy, and the interfacial microstructures and mechanical properties were characterized by SEM, EDX, XRD and universal tensile testing machine. The typical interfacial microstructure was TiB_w/TC4 composite/β-Ti + TiB whiskers/(Ti, Zr)₂(Ni, Cu) intermetallic layer/β-Ti/Ti60 alloy when being brazed at 940 °C for 10 min. The interfacial microstructure evolution was influenced strongly by the diffusion and reaction between molten fillers and the substrates. Increasing brazing temperature decreased the thickness of brittle (Ti, Zr)₂(Ni, Cu) intermetallic layer, which disappeared finally when the brazing temperature exceeded 1020 °C. Fracture analyses indicated that cracks were initialized in the brittle intermetallic layer when (Ti, Zr)₂(Ni, Cu) phase existed in the brazing seam. The maximum average shear strength of joints reached 368.6 MPa when brazing was conducted at 1020 °C. Further increasing brazing temperature to 1060 °C, the shear strength was decreased due to the formation of coarse lamellar (α+β)-Ti structure.     

Formation of Brittle Phases During Pulsed Current Gas Tungsten Arc Welding of Titanium to Aluminum Alloys

Welding of titanium alloy TA15 to aluminum alloy Al 2024 was conducted by pulsed current gas tungsten arc welding using AlSi12 filler metal. Formation process of phases near the Ti/Al interface was discussed. Titanium and aluminum were partially fusion welded in the upper part while brazed together in the middle and bottom parts of the joint. In the upper part of the joint, intermetallics Ti₃Al + Ti₅Si₃, TiAl + Ti₅Si_3, and TiAl₃ were formed as three layers orderly from the titanium side to the weld metal. In the middle and bottom parts of the joint, intermetallics Ti₅Si₃ and TiAl₃ were formed as two layers near the Ti/Al interface.     

TiC增强Cf/SiC复合材料与钛合金钎焊接头工艺分析

采用Ag-Cu-Ti-（Ti＋C）混合粉末作钎料,在适当的工艺参数下真空钎焊Cf/SiC复合材料与钛合金,利用SEM,EDS和XRD分析接头微观组织结构,利用剪切试验检测接头力学性能.结果表明,钎焊后钎料中的钛与Cf/SiC复合材料发生反应,接头中主要包括TiC,Ti3SiC2,Ti5Si3,Ag,TiCu,Ti3Cu4和Ti2Cu等反应产物,形成石墨与钛原位合成TiC强化的致密复合连接层.TiC的形成缓解了接头的残余热应力,并且提高了接头的高温性能.接头室温、500℃和800℃高温抗剪强度分别达到145,70,39 MPa,明显高于Cf/SiC/Ag-Cu-Ti/TC4钎焊接头.     

Cf/SiC复合材料与钛合金(Ti-Zr-Cu-Ni)+W复合钎焊分析

在适当的工艺参数下,用(Ti-Zr-Cu-Ni)+W复合钎料真空钎焊Cf/SiC复合材料与钛合金,采用SEM,EDS和XRD分析接头组织结构,利用剪切试验检测接头的力学性能.结果表明,钎焊时复合钎料中的钛、锆与Cf/SiC复合材料反应,在Cf/SiC复合材料与连接层界面生成Ti3SiC2,Ti5Si3和少量TiC(ZrC)化合物的混合反应层,在连接层与钛合金界面形成Ti-Cu化合物扩散层.增强相钨粉能有效缓解接头的残余热应力,提高接头力学性能,在连接温度930℃,保温时间20 min的工艺条件下,增强相钨粉含量为15%(体积分数)时,接头抗剪强度最高为166 MPa.     

Joining of Cf/SiC Composite and TC4 Using Ag-Al-Ti Active Brazing Alloy

Carbon fiber reinforced SiC (C_f/SiC) composite was successfully joined to TC4 with Ag-Al-Ti alloy powder by brazing. Microstructures of the brazed joints were investigated by scanning electron microscope, energy dispersive spectrometer, and x-ray diffraction. The mechanical properties of the brazed joints were measured by mechanical testing machine. The results showed that the brazed joint mainly consists of TiC, Ti₃SiC₂, Ti₅Si₃, Ag, TiAl, and Ti₃Al reaction products. TiC + Ti₃SiC₂/Ti₅Si₃ + TiAl reaction layers are formed near C_f/SiC composite while TiAl/Ti₃Al/Ti + Ti₃Al reaction layers are formed near TC4. The thickness of reaction layers of the brazed joint increases with the increased brazing temperature or holding time. The maximum room temperature and 500 °C shear strengths of the joints brazed at brazing temperature 930 °C for holding time 20 min are 84 and 40 MPa, respectively.