TC4钛合金/304不锈钢异种材料蜂窝结构钎焊工艺

采用Ti-37.5Zr-15Cu-10Ni和Ag-28Cu两种钎料分别对TC4钛合金面板/304不锈钢蜂窝芯异种材料蜂窝结构进行了钎焊,对钎焊界面组织和蜂窝结构的力学性能进行了对比分析. 结果表明,Ti基钎料与304不锈钢蜂窝芯箔材界面润湿反应性能较差且Ti基钎料钎缝显微硬度较高,导致钎焊界面强度低,蜂窝拉伸力学性能差. Ag基钎料与304不锈钢蜂窝芯箔材和TC4面板均发生显著的界面反应,钎焊温度830 ℃,保温时间10 min时,蜂窝抗拉强度为10.35 MPa,呈蜂窝芯破坏特征. Ag基钎料蜂窝抗拉强度明显优于Ti基钎料结果,适用于TC4钛合金面板/304不锈钢蜂窝芯异种材料蜂窝钎焊.     

TC4钛合金蜂窝板钎焊接头组织性能分析

研究了TC4钛合金蜂窝板的钎焊工艺,试验采用Ti-Zr-Ni-Cu钎料,真空度不低于2×10-3 Pa,钎焊温度为930℃,保温时间为30 min.对焊后试件的钎焊界面组织进行超声无损检测,检测结果表明面板与蜂窝芯钎焊效果极好,未发现有脱焊、虚焊等现象.采用扫描电镜（SEM）和能谱分析（EDS）法进行了试验分析.结果表明,母材和钎料发生相互扩散渗透反应,并出现有新的析出相.该工艺下蜂窝板的界面平均拉脱强度为12.8 MPa,抗剪强度为9.01 MPa,钎焊接头属于脆性断裂.     

钛合金仿莲房特征芯体夹层结构钎焊组织与性能

针对TC4钛合金仿莲房特征芯体与面板钎焊工艺,采用TiZrCuNi钎料,开展了钎焊工艺研究,并分析了主要钎焊工艺参数对钎焊界面组织和夹层结构力学性能的影响。结果表明：钎焊温度920℃,保温时间90min时, TC4钛合金仿莲房特征芯体夹层结构钎焊后界面焊合率良好,界面显微组织为均匀针状α组织和界面金属间化合物,夹层结构平压强度均值为15.14MPa。钎焊保温时间对TC4钛合金仿莲房特征芯体钎焊界面显微组织影响显著,当钎焊保温时间较短时(15min),钎料熔化后,液态钎料中Cu和Ni元素与母材反应时间较短,钎料中Cu和Ni向母材中的扩散反应不充分,钎缝区局部Cu和Ni元素富集导致Cu和Ni元素含量超过共晶成分点,钎焊保温结束后液态钎缝凝固时发生共晶反应,生成块状金属间化合物,钎焊界面主要为含有块状金属间化合物的凝固钎料组织和针状α组织;随着钎焊保温时间的增加,液态钎料中Cu和Ni元素与母材反应时间增加,钎料中Cu和Ni元素向母材中扩散反应深度显著增加,从而Cu和Ni元素在液态钎料中的含量显著降低,元素含量小于共晶成分点,钎焊保温结束后液态钎缝凝固时Cu和Ni元素固溶于β相中,避免大量块状金属化合物生成,随后β相向α相的固态相变时,共析反应生成针状α相,在针状α组织界面处生成金属间化合物。钎焊时间保温时间从15min升至90min时,由于钎焊界面金属间化合物减少,TC4钛合金仿莲房特征芯体夹层结构的平压强度逐渐增加。     

钛合金仿莲房芯体夹层结构钎焊界面组织与性能

针对TC4钛合金仿莲房特征芯体与面板钎焊工艺,采用TiZrCuNi钎料开展了钎焊工艺研究,并分析了主要钎焊工艺参数对钎焊界面组织和夹层结构力学性能的影响。结果表明:钎焊温度920℃,保温时间90min时,TC4钛合金仿莲房特征芯体夹层结构钎焊后界面焊合率良好,界面显微组织为均匀针状α组织和界面金属间化合物,夹层结构平压强度均值为15.14 MPa。钎焊保温时间对TC4钛合金仿莲房特征芯体钎焊界面显微组织影响显著,当钎焊保温时间较短(15 min)时,钎料熔化后,液态钎料中Cu和Ni元素与母材反应时间较短,钎料中Cu和Ni向母材中的扩散反应不充分,钎缝区局部Cu和Ni元素富集导致Cu和Ni元素含量超过共晶成分点,钎焊保温结束后液态钎缝凝固时发生共晶反应,生成块状金属间化合物,钎焊界面主要为含有块状金属间化合物的凝固钎料组织和针状α组织;随着钎焊保温时间的增加,液态钎料中Cu和Ni元素与母材反应时间增加,钎料中Cu和Ni元素向母材中扩散反应深度显著增加,从而Cu和Ni元素在液态钎料中的含量显著降低,元素含量小于共晶成分点,钎焊保温结束后液态钎缝凝固时Cu和Ni元素固溶于β相中,避免大量块状金属化合物生成,随后发生β相向α相的固态相变时,共析反应生成针状α相,在针状α组织界面处生成金属间化合物。钎焊保温时间从15 min升至90 min时,由于钎焊界面金属间化合物减少,TC4钛合金仿莲房特征芯体夹层结构的平压强度逐渐增加。     

GH3536蜂窝钎焊界面组织与性能北大核心

针对GH3536高温合金开展研究,以提供一种用于小芯格且薄壁的高温合金蜂窝的高强度钎焊工艺。采用芯格内切圆直径为0.8 mm、蜂窝壁厚为0.05 mm的GH3536蜂窝,使用BNi2粘带钎料,优化了钎料用量、分析了不同钎料用量对应钎焊蜂窝界面组织形貌,并测试了GH3536蜂窝元件的拉伸性能、压缩性能及弯曲强度,评价GH3536蜂窝元件的基础力学性能。结果表明,所获得蜂窝结构焊合率达到99.5%;钎焊蜂窝界面晶粒细小、组织均匀、无钎缝溶蚀;GH3536蜂窝元件具有优异强韧性、平面抗拉强度达到50 MPa。     

TC4/30CrMnSiNi2A钎焊接头组织与力学性能分析

采用Ti-37.5Zr-15Cu-10Ni和 Ag-Cu28两种钎料分别对TC4钛合金/30CrMnSiNi2超高强钢异种材料进行了钎焊,对钎焊界面组织以及接头的力学性能进行了分析。结果表明：Ag基钎料钎焊TC4与30CrMnSiNi2A异种材料时,钎缝界面组织为Ag(s,s)+Ti-Cu系化合物组成;因Ag固溶体的存在,钎缝具有一定的韧性,接头剪切强度较高,剪切断口呈现出韧性断裂特征。Ti基钎料钎焊TC4与30CrMnSiNi2A异种材料时,钎缝界面组织为Ti-Zr固溶体+未完全反应凝固钎料,钎缝显微硬度较高,接头剪切强度较低,呈现出脆性断裂特征。Ag基钎料TC4/30CrMnSiNi2A异种材料钎焊接头力学性能明显优于Ti基钎料结果,在钎焊温度830℃,保温时间15min时,剪切强度为125.52MPa。     

B-Ti57CuZrNi钎料对接钎焊TC4钛合金接头的组织和性能

采用B-Ti57CuZrNi钎料对TC4钛合金进行了对接钎焊,研究了B-Ti57CuZrNi钎料在TC4钛合金表面的润湿性和钎焊工艺参数对TC4钛合金钎焊接头微观组织和力学性能的影响。结果表明,B-Ti57CuZrNi钎料在TC4钛合金表面铺展良好,形成了有效的冶金结合。随钎焊温度和保温时间的增加,钎缝整体宽度变宽,向焊缝中心生长的针状α相变多变长。焊接温度低且保温时间短时,接头组织存在大块富Cu、Ni白色铸造组织。钎焊温度为930℃、钎焊时间为15 min时,接头室温抗拉强度低,易脆断于焊缝,而钎焊时间低于30 min时的室温断后伸长率较低。高钎焊温度(>960℃)和长保温时间(>45 min)对钎焊接头400℃抗拉强度和断后伸长率均不利。从获得钎焊接头优良的室温和400℃拉伸性能来考虑,宜选取钎焊温度为950℃,保温时间为30 min。     

纯铝1060/镀锌钢电阻点钎焊工艺及接头性能

采用电阻点钎焊进行了纯铝1060与SGCC热镀锌钢板的搭接试验,研究了接头界面组织,并测试了接头力学性能. 结果表明,试验所用铝硅（Al-Si）合金钎料润湿良好,焊后接头焊缝界面处产生了具有双层结构且厚度不均的金属间化合物,厚度小于10 μm;焊接电流为7.8 kA时,接头抗拉剪载荷达到峰值,约为4.72 kN,在相同工艺参数下,电阻点钎焊接头的抗拉剪载荷明显高于点焊接头;接头断裂大都发生在铝板侧,且主要在热影响区处而不在焊点处,说明点钎焊接头质量良好,但由于焊缝铝侧界面局部存在“未钎合”缺陷,焊缝界面会产生拉应力且在金属间化合物的应力作用下易产生裂纹.     

AlSiNi钎料感应钎焊铝/钢接头的组织和力学性能

借助润湿试验、热分析等手段分析了AlSi12钎料和AlSiNi钎料的钎焊工艺性.使用扫描电镜、能谱分析、力学性能测试等手段分析了AlSi12,AlSiNi钎料钎焊铝/钢接头的组织形貌、断口形貌、相组成和力学性能.结果表明,AlSiNi钎料对钢的润湿性优于AlSi12钎料,但钎料熔化区间稍有扩大;在焊缝/钢界面处,AlSiNi钎料钎焊接头金属间化合物层的厚度为8.1 μm,比AlSi12钎料钎焊接头金属间化合物更薄,分布也更均匀;AlSiNi钎料钎焊接头中的含Ni金属间化合物塑韧性更好,与母材钢的结合力更强,AlSiNi钎料钎焊铝/钢接头抗拉强度高于AlSi12钎料钎焊接头.     

SP700/TC4钛合金蜂窝夹层结构钎焊工艺分析

采用非晶态Ti-Zr-Cu-Ni箔带钎料对SP700/TC4钛合金蜂窝结构进行钎焊工艺研究,分析了钎焊温度和保温时间对钎焊接头组织和力学性能的影响. 结果表明,当钎焊温度在875～890 ℃之间变化时,随温度升高,钎焊接头中元素扩散更为充分,接头拉脱强度持续增长;在890 ℃下保温2～4 h不同时长进行钎焊,接头的拉脱强度先逐渐增加,在保温时间为3.5 h时达到最大值,随后逐渐降低. 获得SP700/TC4钛合金蜂窝结构的较优钎焊工艺为890 ℃/3.5 h,该工艺下钎焊接头的室温拉脱强度、三点弯曲强度、平面压缩强度、L及W方向抗剪强度分别达到14.64,224.05,11.21,4.43及3.76 MPa,破坏部位均为TC4蜂窝芯.     

Finite element modelling of brazed residual stress and its influence factor analysis for stainless steel plate-fin structure

This paper presents a finite element modelling of brazed residual stress in a stainless steel plate-fin structure applied to recuperators in microturbines. The effects of nine influence factors on residual stress are investigated. The results show that the brazed joint creates large residual stresses due to the mechanical properties mismatching between base metal and filler metal. Strength in the middle joint is affected mainly by longitudinal stress. The residual stress gradient around the interface between base metal and filler metal is very large, which can have a great effect on interface strength. The material mismatching, brazing gap, pressure loading, fin pitch, fin thickness, fin height and plate thickness significantly affect the residual stress distribution, while the brazing temperature and the number of fin layers have little impact on residual stress. This work provides a reference for optimizing the brazing procedure and decreasing the residual stress for stainless steel plate-fin structures.     

用Al—Ti—Al合金钎料复合板钎焊钛的研究

介绍了用Ａｌ－Ｔｉ－Ａｌ合金金属复合板钎焊工业纯钛的研究结果。这种金属复合板是采用特殊的轧制复合工艺加工而成的。复合板的两个外表面包含一层０．１ｍｍ厚的Ａｌ合金钎料,其中间夹层是０．４ｍｍ厚的工业纯然板。在本实验中用这种复合板替代传统单一的Ａｌ合金钎料薄片来钎焊钛的蜂窝结构,其结果是简化了钎焊工艺,使焊点更加均匀。同时还研究籽焊缝的剪切强度,宏观和显微组织。并比较了用单一Ａｌ合金钎料薄片钎焊和用该     

钎焊超薄GH99蜂窝夹层结构力学性能分析

以制造轻量化超薄金属热防护结构为目标,首先采用真空钎焊方式制备了GH99超薄夹层结构;通过光学显微镜及扫描电子显微镜对夹层结构的钎焊界面及母材的微观组织进行了表征;通过万能试验机对夹层结构的界面剥离强度、面内与面外压缩性能进行了测试,并与有限元模拟结果进行对比.结果表明,钎焊前后母材晶粒由退火态孪晶组织转变为等轴组织;钎焊接头主要为Ni(s, s)和Ni₃Si的共晶组织,并伴随部分Cr(Mo, Ni)固溶体、Ni₂Si及NiSi₂相;界面剥离在薄壁面板上失效;夹层结构面内与面外的压缩失效均表现为屈曲失效,模拟结果与试验结果一致.     

Microstructure and Property of Cu/Al Joint Brazed with Al-Si-Ge Filler MetalEI北大核心CSCD

Cu/Al brazing has good prospect for applications in the air conditioning and refrigeration industry. A suitable filler metal is the key of Cu/Al brazing. The chemical and physical properties of the filler metal have great influence on the brazing process and parameters. And the strength of the brazing joint is closely related to the properties of the filler metal and the brazing process. While the previous studies have not developed a kind of Cu/Al brazing filler metal which can achieve a tough joint at a low brazing temperature. In this work, the Al-5.6Si-25.2Ge filler metal was first used to braze Cu/Al dissimilar metals, and the melting characteristics of the filler metal, spreading wettability, Cu interfacial structure and strength of brazed joint were investigated systematically. Additionally, the common Zn-22Al filler metal was also used for comparison. The results show that the Al-5.6Si-25.2Ge filler metal possesses low melting temperature (about 541 degrees C) and excellent spreading wettability on Cu and Al base metals. The interfacial structure of Al-5.6Si-25.2Ge/Cu was CuAl2/CuAl/Cu3Al2. The thickness of planar CuAl and Cu3Al2 phases was only 1 similar to 2 mu m, and the thickness of cellular CuAl2 phase was about 3 mu m. The interfacial structure of Zn-22Al/Cu was CuAl2/CuAl/Cu9Al4, but the average thickness of the CuAl2 layer was up to 15 mm. The test results of the shearing strength show that the shearing strength of the Cu/Al joint brazed with Zn-22Al filler metal was only 42.7 MPa, but the shearing strength brazed with Al-5.6Si-25.2Ge filler metal was higher (53.4 MPa).     

铝/钛异种金属填丝电子束熔钎焊接头组织与性能

采用填丝电子束熔钎焊对TA2纯钛和1060纯铝进行了焊接试验,分别对接头显微组织、相组成、抗拉强度和显微硬度进行了分析. 结果表明,采用填丝电子束熔钎焊可以实现纯钛与纯铝的有效连接,接头抗拉强度为98.8 MPa,达到铝母材的96.7%. 接头呈现典型的熔钎焊特征,由钛侧钎焊接头及铝侧熔焊接头组成. 熔钎焊界面存在Ti-Al金属间化合物层,其厚度小于2 μm,未对接头性能强度产生影响. 铝侧熔化区内存在散布的金属间化合物起到一定强化作用,显微硬度最低值位于铝侧热影响区内,拉伸断裂于该区域.     

热浸镀锡铜磷钎料的性能

以Cu93P钎料为基体,在其表面热浸镀锡,制备CuPSn钎料,采用扫描电镜、万能力学试验机、显微硬度计、差热分析仪、箱式电阻炉和体视显微镜分析锡镀层的界面形貌,钎料的抗拉强度、显微硬度、熔化温度和润湿性。结果表明：在Cu93P钎料表面热浸镀锡过程中,液态锡与钎料发生了界面反应,生成Cu₆Sn₅金属间化合物,即钎料基体与锡镀层形成良好的冶金结合;随着热浸镀温度的升高和时间的延长,CuPSn钎料的抗拉强度和显微硬度均呈降低趋势,抗拉强度的降低源于界面处产生的Cu₆Sn₅脆性化合物和孔洞,显微硬度的降低源于热浸镀的去应力退火作用;Cu93P钎料表面热浸镀锡可降低钎料的熔化温度,提高钎料的润湿性,Cu93P钎料表面热浸镀5.20%（质量分数）锡之后,Cu88.16P6.64Sn5.20在纯铜板上的润湿铺展面积比基体Cu93P钎料增加43.15%。     

Interfacial Microstructure Evolution and Shear Strength of Titanium Sandwich Structures Fabricated by Brazing

The corrugated sandwich structure, consisting of a CP Ti (commercially pure titanium) core between two Ti-6Al-4V face sheets, was brazed using pasty Ti-37.5Zr-15Cu-10Ni as filler alloy, at the temperature of 870°C for 5, 10, 20, and 30 min. The effect of brazing time on the microstructure and elemental distribution of the brazed joints was examined by means of SEM, EDS, and XRD analyses. It was found that various intermetallic phases were formed in the brazed joints, following a brazing time of 5 min, and their contents were decreased by the increment of brazing time, while prolonged brazing time resulted in a fine, acicular Widmanstätten microstructure throughout the entire joint. In addition, shear testing was performed in the brazed corrugated specimens in order to indirectly assess the quality of the joints. The debonding between CP Ti and Ti-6Al-4V was observed in the specimen brazed for 5 min and the fracture of the CP Ti corrugated core occurred after 30 min of brazing time. Additionally, when brazed for 10 min or 20 min, brittle intermetallic compounds in the joints and the grain growth of the base metal were controllable. Therefore, the sandwich structures failed without debonding in the joints or fracture within the base metal, demonstrating a good combination of strength and ductility.