The study on interfacial bonding strength of Ag-Ni, Ag-Cu in cold pressure welding

The area of combination actually is a kind of interfacial phenomena that exist on the surface or thin film. The properties of interface have important effect on the whole welded joint, even decide directly the interfacial bonding strength.The bonding strength of metals in cold pressure welding such as Ag-Ni (they are hardly mutual soluble ) and Ag-Cu( they are limited soluble ) are discussed in this paper. The results of the tensile test suggest that two kinds of welded joints have enough strength to satisfy with the demand for being used. Moreover, thermodynamics, crystal logy, physics and metal electronic microscopic analysis etc are adopted to further calculate the bonding strength. The results of test and theoretical analyses prove that Ag-Ni, Ag-Cu, especially, for Ag-Ni can .form strong welded joint which is higher than that of the relative soft base metals in cold pressure welding.     

爆炸焊接记忆合金Ni50Ti50与Cu界面扩散机理的研究

为了揭示焊接界面细观尺度扩散特征,采用内嵌入势函数（EAM势）通过对形状记忆合金Ni50Ti50和Cu进行爆炸焊接界面分子动力学数值模拟,同时结合SEM、EDX测试方法对爆炸焊接界面微细观形貌及物理特征实验分析,研究结果表明以记忆合金Ni50Ti50与Cu在采用uz= -1500 m/s, ux= 700 m/s冲击碰撞工况下,体系的压强震荡逐渐变小,120ps以后已经趋于平衡,体系的温度稳定在1350K左右,而压强稳定在28GPa左右; 在扩散层两侧Cu的原子浓度一直维持在5%左右,Ni和Ti的原子浓度在47%上下波动,界面扩散层厚度在1.03μm~1.45μm的范围内;实验结果采用SEM、EDS微观分析验证了获得焊接界面扩散层厚度约为1.56μm,基本与计算结果相一致。     

钛/铝异种合金电弧熔钎焊接头界面特征及力学性能

采用AlSi5焊丝和交流TIG电弧实现了TC4钛合金和6056铝合金的熔钎焊连接,通过金相显微镜(OM)、扫描电镜(SEM)、能谱分析仪(EDS)和拉伸试验等方法评价了接头界面微观组织特征和力学性能.结果表明,当焊接电流为30,40和60 A时,界面反应层分别呈棒状、块状和锥状分布,过大的热输入使界面产生了粗大柱状金属间化合物层,冷却时在焊接内应力作用下产生了冷裂纹.金属间化合物主要为TiAl3相,Si元素偏聚其内形成过饱和固溶体.接头强度-焊接电流曲线出现了两次峰值强度.焊接电流为30 A时,熔钎焊接头平均抗拉强度为103 MPa.焊接电流为60 A时,电弧形态扩张使能量密度降低,接头强度出现第二次峰值.     

AlLY12爆炸焊接界面疲劳裂纹的扩展行为

采用纯铝／硬铝（Al/LY12)爆炸复合板通过电子束焊接制得界面裂纹四点弯曲试样,由于强度错配,Al/LY12界面裂纹顶端局部的变形是锐化与钝化的复合型,但在疲劳载荷下其整体裂端应力应变场仍然可由纯1型应力强度因子主导,可以采用和单材料试样相同的方式进行界面裂纹的疲劳扩展行为研究,界面裂纹可在较低的外载水平下启努扩展,但爆炸焊接界面存在的波纹使得界面裂纹的扩展速率出现波动,并且阻碍裂纹的扩展,相同外载下Al/LY12界面裂纹的疲劳扩展速率低于单材料LY12的疲劳扩展速率。     

热压焊接制备的Cu / Al双金属的界面组织和剪切强度

采用扩散焊（DFW）技术制备了Cu/Al双金属,连接温度范围683-803K,连接时间范围20-80min,连接压力15MPa。Cu/Al双金属界面处的SEM试验结果表明,随着焊接温度的升高和保温时间的延长,界面层厚度逐渐增加,在连接温度为803K,连接时间80min,Cu/Al界面处形成了Al4Cu9,Al3Cu4,AlCu、Al2Cu金属间化合物（从铜侧到铝侧）,根据扩散动力学,金属间化合物(IMCS)的生成顺序为Al2Cu、Al4Cu9、AlCu、Al3Cu4。Cu / Al双金属的剪切试验显示为脆性断裂,并且界面强度随着IMC的减少而增加。在723 K的焊接温度下进行20分钟焊接后,Cu / Al双金属的剪切强度最高为63.8 MPa。     

焊接能量对Mg/Ti超声波焊接接头微观组织与力学性能的影响

采用超声波焊接技术对Mg/Ti异种金属进行了焊接,研究了不同焊接能量对接头界面峰值温度、界面形貌、界面原子扩散程度以及力学性能的影响规律。研究发现:Mg/Ti超声波焊接接头整体界面较平直,局部界面有较小起伏,未发现裂纹、未熔合等缺陷,也未看到明显的反应层;随着焊接能量的增大,界面峰值温度升高,原子扩散层厚度增大,连接区面积逐渐增大,接头力学性能得到提高,而能量达到2000J时镁侧母材出现裂纹;接头断裂模式分为界面断裂和纽扣断裂,界面断裂时断裂发生在镁侧扩散层区域和镁侧非扩散层区域。扫描电子显微镜和X射线衍射仪分析表明,Mg/Ti连接界面区域无明显的金属间化合物生成。     

Radial friction welding interface between brass and high carbon steel

CT-130 special inertia friction welding machine is used to finish a large size (156 mm diameter) of H90 brass/D60 steel dissimilar welding. SEM, EDS methods are used to analyze the interfacial characteristics of H90/D60 welding joint. The results show that in the welding interface, some furrow-shaped holes appear at the end of welding joint, and a smooth line occurs in the central welding interface and a good welding seam is formed. Thermoplastic brass is droved and flowed to the edge of welding interface under radial pressure, which becomes a lubricating thin film, and reduces the friction coefficient of welding joint edge, leads to that phenomenon. It is found that Fe and Cu elements diffusion appeared at the welding interface. But the density and distance of Fe element diffusion towards H90 brass are larger than that of Cu element towards D60 steel, which is attributed to the difference of the lattice coordination number of Fe/Cu.     

Ni在钢/铝电阻点焊中的作用

以DC01钢板与5082铝合金板为基材,在电极压力3 kN、焊接时间300 ms、保持时间100 ms条件下,研究了电阻点焊中焊接电流(9~12 kA)及Ni镀层对接头剪切力、正拉力、界面相组成的影响。结果表明,随焊接电流的提高,熔核尺寸增大,接头力学性能提高。剪切力比正拉力高一个数量级。在10 kA焊接电流下,镀Ni钢/铝接头的剪切力和正拉力均比钢/铝直接焊接时强度明显提高,这与钢/铝界面形成了Al 3Ni合金相,抑制了脆性Fe 2Al 5金属间化合物的生成有关。     

Diffusion welding process and joint''''s microstructure behavior of SiC_w/6061Al composite

The rules such as process parameters affecting joint properties and the evolution principle of weld's microstructure have been researched by adopting diffusion welding process to connect SiCw/6061Al composite. Experimental results show that there exists a critical temperature region between solid and liquid phase line of SiCw/6061 Al composite, and the region will shrink with the increasing of welding pressure. When diffusion welding occurred under the critical temperature region, welding joint exhibits bad property of bonding, and the matrix and the reinforcement can't bond effectively. When diffusion welding occurred in the critical temperature region, the strength of welding joint changes widely with the variation of welding temperature. When welding temperature varies in 10癈, the strength of welding joint will change obviously. Only when welding temperature is higher than the critical temperature region, stable joint properties can be obtained. Simultaneously the matrix and the reinforcement has bet     

低活化马氏体钢真空扩散焊接工艺

在不同工艺参数下对低活化马氏体钢进行真空扩散焊接试验,通过比较试样显微组织形态、界面结合率及抗拉强度,探究焊接温度、焊接压力对接头组织演化及力学性能的影响. 结果表明,马氏体组织在扩散焊接过程中发生了奥氏体化现象,且焊接温度越高时,奥氏体化程度越高;在一定范围内,提高焊接温度及焊接压力均可增强原子的自扩散效果,从而提升焊缝接头的力学性能,其中焊接温度1 000 ℃,焊接压力20 MPa,保温时间120 min参数下焊接试样的抗拉强度达到1 013 MPa,焊接面结合状况良好.     

铝基复合材料SiCW/6061Al的激光焊接

采用脉冲激光焊接工艺研究铝基复合材料SiCw/6061Al的焊接性,着重探讨激光输出功率（P）、脉冲频率（f) 对接头性能的影响,借助X射线衍射、扫描电镜、透射电镜等手段分析接头组织。研究发现,焊缝中存在的界面反应物、气孔缺陷,是导致该种材料焊接性显著降低的主要因素。进一步研究表明,在激光焊接条件下铝基复合材料界面反应是不可避免的,反应物沿热流方向生成,具有一定的方向性,激光输出功率是影响SiC-Al界面反应的主要因素,同时提高脉冲频率将对界面反应有一定的抑制作用;焊缝中气孔随激光脉冲频率的增大而减少直至消失。在此基础上,通过制定合理的焊接工艺,获得了成形良好的铝基复合材料激光焊焊缝。     

钛/钢爆炸复合板界面连接机理与力学行为

本文表征了钛/钢爆炸焊接复合板的界面组织和剪切性能,研究爆炸复合过程的界面结合机理。结果表明,在金属板之间形成了波状界面组织,剧烈塑性变形造成钢基体发生明显的塑性流动,并在界面形成连续的漩涡形貌。TEM和XRD检测证实界面存在纳米尺度的过渡层,并包含有固溶体组织和少量金属间化合物。波状界面组织改善了复合板沿爆炸方向的界面剪切强度,剪切断口显示漩涡组织发生韧性断裂形貌。     

Effect of Initial Hardness on Interfacial Features in Underwater Explosive Welding of Tool Steel SKS3

This paper aims at investigating effects of initial hardness on interfacial features for identical compositional materials under identical welding conditions. Two underwater explosive welding experiments on tool steel SKS3 with copper foil were carried out: one as-received and the other heat-treated. The welding process was simulated using the commercially available software package LS-DYNA. Numerical simulation gave deformation of the flyer/base plate and pressure distribution during the welding process. Microstructure and hardness at interface of the welded metals were evaluated. The results indicate that decreasing impact energy is accompanied by a shift from wavy to linear interface. Moreover, a comparison of the two experiments allows the conclusion that high initial hardness results in a decrease of wavelength and amplitude under identical welding conditions. Hardness profiles of as-received tool steel-copper welding reveal the hardening effect of impact in the vicinity of the interface. However, of interest is that a decrease in hardness was seen in the case of heat-treated martensitic tool steel with copper, fundamentally differing from previous explosive welding research; phase transition is proposed to discuss the relation between the effects of impact and heat, and those of work hardening and softening.     

NEW ACHIEVEMENTS ON THE THEORY AND TECHNOLOGY OF EXPLOSIVE WELDING

There are four new achievements of this work on the theory and technology of explosive welding.(1) It has been found and defined three kinds of bonding interfaces: big wavy, small wavy and micro wavy, and the micro wavy interface is the best. In a cladding plate, it is for the first time to find that the form of interface presents regular distribution.(2) Although the interface has the features of melt, diffusion and pressure welding in the mean time, the seam and "hole" brought by the melt weaken the bonding strength of interface greatly, and the effect of melt on interface must be eliminated in explosive welding, so explosive welding is not a melt weld. The diffusion welding is a kind of form of pressure welding, and the diffusion is not the reason of the bonding of interface but the result of interface high pressure. So the diffusion welding cannot also explain the bonding mechanism of it. The experiment and theory make clear that explosive welding is a special pressure one.(3) To get good interface     

爆炸焊接法制备铟/铁复合板的实验与数值模拟

提出了一种通过在炸药与复合板之间增加一层速度调整板，以获得理想焊接条件的用于制备铟/铁复合板的新型爆炸焊接方法。通过理论方法计算了爆炸焊接参数，通过实验对炸药载荷的影响进行了研究。应用光滑粒子流体动力学（SPH）方法进行数值模拟以验证参数有效性，探究了结合界面的成型机理，并研究了压力和塑性应变的分布。结果表明，当炸药厚度增加时，界面波形结构更明显。界面剪切试验结果表明铟/铁复合板结合面抗剪切强度为16 MPa，比纯铟材料的抗剪切强度高，且三点弯曲试验之后复合板结合界面无裂纹。采用改进的爆炸焊接方法可以有效制备高质量铟/铁复合板。     

锆钢爆炸复合板界面波形影响参数研究

为了研究爆炸焊接参数对锆钢复合板界面波的影响,对锆钢进行了小倾角法爆炸焊接,在不同碰撞速度和碰撞角条件下,得到了连续变化的界面波。通过对界面波进行金相显微观察,测量了不同位置界面波的波长和波高。采用SPH无网格方法对小倾角法爆炸焊接过程进行了数值模拟,计算出了不同位置的碰撞速度、碰撞角、比压强。研究表明,碰撞速度和碰撞角是影响界面波形的关键参数,当碰撞速度为493 m/s,碰撞角为9.8°时,开始产生界面波。随着碰撞速度和碰撞角的增加,界面波波长逐渐增加,比波长先减小后增加。     

炸药爆炸速度对铝/钛爆炸焊接复合管结合界面及性能的影响

通过在粉状乳化炸药中添加不同比例密度调节剂,配制了自然堆积状态下爆炸速度范围为1450~2550m/s的低爆炸速度炸药;采用该爆炸速度炸药进行了铝/钛复合管爆炸焊接试验,结合最小碰撞速度理论,对试验结果及其界面微观结构和结合强度测试进行了分析.结果表明,该复合管爆炸焊接的合适爆炸速度约为1950~2150m/s,其结合质量能够满足后续加工要求;爆炸速度对复合管的界面结合波形影响很大,且复合管前端波幅较小,沿着爆轰传播方向逐渐增大,至末端时又变小,波形且呈现不太规则的扁平波状结合现象,分析认为主要是因为在复合管的爆炸焊接环境和爆炸产物飞散条件与复合板不同所致.     

电子束焊-钎焊复合焊T形接头组织性能分析

实现了TA15钛合金T形接头的电子束焊-钎焊复合焊接.采用扫描电镜、能谱分析仪和X射线衍射分析仪等测试手段,对接头的微观组织形貌、元素成分分布和界面反应产物等进行分析研究.并分别对复合焊接头和电子束焊接头的弯曲性能进行了比较分析.结果表明,在适当的工艺条件下,可以实现TA15钛合金T形接头的电子束-钎焊复合焊接.在电子束焊缝和钎焊缝的界面处存在Cu,Ni元素的扩散和界面反应.复合焊接头的塑性要优于电子束焊,其所承受的最大压强略低于电子束焊.     

Development of a bonding interface between steel/steel and steel/Ni by ultrasonic welding

Ultrasonic welding is a solid-state welding technique that can bond materials at a relatively low temperature and pressure. In this study, steel/steel and steel/Ni combinations were successfully bonded by ultrasonic welding, and the development of the bonding interface was examined. The bonding strength was obtained by a lap shear test and increased with welding time, as did the fraction of bonded area observed by SEM. The bonding process sequence was investigated by SEM and electron backscatter diffraction (EBSD) analysis of a cross-section at the bonding interface. It was revealed that abrasion is caused by oscillation to form small particles consisting of steel and Ni and that the particles are grown and subsequently flattened with welding time. Bonding is achieved by the flattened particles spreading along the bonding interface without any voids.     

钛/钢复合板爆炸焊接试验及结合界面研究

为探讨造成钛/钢爆炸焊接复合板结合质量差、末端易出现不同程度开裂区域的原因,进行了钛/钢复合板的爆炸焊接试验,并对结合界面进行了光学金相分析(OM)、电镜扫描(SEM)及能谱线扫描(EDS)。结果表明,平行于结合界面的剪应力是结合界面的主要受力状态;复合板末端处平行于结合界面的剪应力过大、沿部分已焊接界面和Fe基体一侧撕裂,是造成复合板末端开裂的主要原因;优化装药工艺可减小结合界面脆性金属间化合物层的厚度、减缓末端的开裂程度,并显著提高焊接质量。