（WC—Co／NiCrBSi）钎焊涂层结合机制及磨损性能研究

采用真空钎焊工艺,将ＷＣ－Ｃｏ硬质合金粉和ＮｉＣｒＢＳｉ（ＡＷＳＢＮｉ－２）合金粉钎焊到４５＃钢表面,得到（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）钎焊涂层。     

(WC-Co/NiCrBSi)钎焊涂层结合机制及磨损性能研究

采用真空钎焊工艺,将ＷＣ－Ｃｏ硬质合金粉和ＮｉＣｒＢＳｉ（ＡＷＳＢＮｉ－２）合金粉钎焊到４５＃钢表面,得到（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）钎焊涂层。不同钎焊工艺下,涂层及涂层／基体的拉伸强度分别达１００—１４０ＭＰａ和３００－３６０ＭＰａ。初步分析了钎焊涂层结合机制。涂层的磨料磨损性能远高于同配比的火焰堆焊涂层及Ｃｏ－Ｃｒ－Ｗ堆焊层     

Co—Ti,Ti—Zr—Cu高温钎料在Si3N4陶瓷上润湿性与界面连接

设计了Ｃｏ－Ｔｉ，Ｔｉ－Ｚｒ－Ｃｕ两种高温钎料，进行了它们与Ｓｉ３Ｎ４表面的润湿性实验，利用ＸＲＤ分析钎焊合金与陶瓷界面，结果表明Ｃｏ－Ｔｉ合金中Ｔｉ以化合形态形式存在时，钎料不润湿Ｓｉ３Ｎ４陶瓷，钎焊合金与陶瓷间的办面连接强度与基体材料及界面反应产物密切相关。     

金属的化学成份对金属／ZrO_2连接的影响

研究了４Ｊ３３、纯Ｎｉ和４０Ｃｒ钢与ＺｒＯ_２的钎焊连接。结果表明：对Ａｇ_（６６）Ｃｕ_（３０）Ｔｉ_４活性钎料，４Ｊ３３与ＺｒＯ_２在１１８３Ｋ时能形成连接，而在１１０３Ｋ与１１３３Ｋ时连接失败；纯Ｎｉ与ＺｒＯ_２在温度升至１２７３Ｋ仍不能形成连接。这是因为纯Ｎｉ和４Ｊ３３所含的Ｆｅ、Ｎｉ、Ｃｏ元素扩散到钎料中并与之发生反应形成化合物所致。４０Ｃｒ钢和ＺｒＯ_２的连接钎料中未形成化合物，它们在１１３３Ｋ就能形成连接。     

BCu50ZnMnNiSi多元铜基钎料的研究

提出了一种含Ｎｉ、Ｓｉ的适合钎焊合金白口铸铁的Ｃｕ基ＣｕＺｎＭｎ多元钎料,并对ＢＣｕ５０ＺｎＭｎＮｉＳｉ钎料的熔化特性、钎焊工艺性能、钎料组织以及力学性能进行了研究。研究结果表明,与普通ＣｕＺｎ合金钎料比较,ＢＣｕ５０ＺｎＭｎＮｉＳｉ钎料钎焊冶金特性优异,界面冶金结合致密,尽管钎料中含有多元合金元素,钎焊后钎缝仍有较好的塑必     

Ni_3Al(IC-6)合金防护涂层抗氧化性能研究

Ｎｉ３Ａｌ合金是一种新型高温合金，ＩＣ－６合金是不含Ｃｒ而含１４％Ｍｏ的Ｎｉ３Ａｌ合金。由于高温下Ｍｏ极易氧化升华，因此为使ＩＣ－６合金在高温下可靠工作，需选择ＮｉＣｒＡｌＸ涂层作为ＩＣ－６合金的保护涂层。采用磁控溅射技术，在专用装置上按通过系统研究提出的工艺涂覆ＮｉＣｒＡｌＸ涂层，并对其抗周期氧化性能进行了研究。试验表明：ＮｉＣｒＡｌＹＳｉ涂层对ＩＣ－６合金的防护是非常有效的。     

Ni3Al（IC—6）合金防护涂层抗氧化性能研究

Ｎｉ３Ａｌ合金是一种新型高温合金，ＩＣ－６合金是不含Ｃｒ而含１４％Ｍｏ的Ｎｉ３Ａｌ合金。由于高温下Ｍｏ极易氧化升华，因此为使ＩＣ－６合金在高温下可靠工作，需选择ＮｉＣｒＡｌＸ涂层作为ＩＣ－６合金的保护涂层。     

Ni－Cr－Al电极材料的组织与性能

研究了Ｎｉ３Ａｌ—ＸＣｒ、ＮｉＡｌ—ＸＣｒ二个系列合金的显微组织与结构，并对合金的导电率、维氏硬度和三点弯曲性能进行了测试。本文还就不同Ｃｒ含量对合金性能的影响关系以及Ｎｉ—Ｃｒ—Ａｌ合金作为真空断路器（ＶＣＢ）电极材料的应用前景作了进一步的讨论．     

钎焊工艺对WC—Co／NiCrBSi复合涂层性能的影响

采用真空钎焊技术,在４５＾＃钢基体表面焊一层（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）复合涂层,研究了不同钎焊工艺对涂层自身结合强度、涂层与基体间连接强度以及涂层抗磨料磨损性能的影响。钎焊工艺为１０８０℃×１０ｍｉｎ时,涂层自身结合强度为１４６ＭＰａ;涂层与基体间的最高连接强度为３６７ＭＰａ。涂层的抗磨料磨损性能比Ｃｏ－Ｃｒ－Ｗ堆焊涂层和（ＷＣ－Ｃｏ／ＮｉｒＢＳｉ）火焰堆焊层的高。     

齿科铸造Co—Cr合金组织和性能的研究

牙科铸造用Ｃｏ－Ｃｒ合金在真空感应炉中进行熔配，浇成小铸锭。用高频高心铸造机进行合金二次重熔，铸成假牙修复体。本文系统地研究了Ａｌ、Ｓｉ、Ｃｒ、Ｃ、Ｎｉ等合金元素对Ｃｏ－Ｃｒ合金机械性能、铸造性能和化学稳定的作用，对筛选出的综合性能优良的ＣＷ－Ｈ型Ｃｏ－Ｃｒ合金进行了动物试验，临床应用效果良好。     

采用BNi-7的Ti（C，N）基金属陶瓷与17-4PH沉淀硬化不锈钢的真空钎焊研究

采用镍基共晶钎料BNi-7对Ti（C,N）基金属陶瓷与17—4PH沉淀硬化不锈钢行了真空钎焊连接。研究了钎焊温度和焊缝厚度对焊接接头力学性能和微观结构的影响。结果表明,BNi-7对金属陶瓷粘结相具有较强的溶解能力,这是熔降元素（磷）能够在金属陶瓷侧大范围分布、钎焊接头获得良好界面结合的主要原因。随钎焊温度升高,磷在金属...     

Brazing of 422 stainless steel using the AWS classification BNi-2 Braze alloy

The study of brazing 422 stainless steel (422SS) using the AWS classification BNi-2 braze alloy as the filler metal is evaluated in the study. The BNi-2 braze alloy demonstrates excellent wettability on the 422SS substrate for temperatures exceeding 1025 °C. The brazed joint is primarily comprised of the Ni-rich matrix and chromium boride. Additionally, the B–Cr–Fe precipitates are formed at the interface between the braze and 422SS. Some Kirkendall porosity is also observed in the braze close to the interface, due to nonsymmetrical interdiffusion between the braze and 422SS substrate. Shear strengths of brazed joints are varied from 306 to 481 MPa. The infrared brazed specimen shows the highest shear strength among all brazed specimens. Increasing brazing temperature and/or time result in decreased shear strength of the brazed joint.     

Effects of Al2O3 Particulates on the Thickness of Reaction Layer of Al2O3 Joints Brazed with Al2O3-Particulate-Contained Composite Filler Materials

In order to understand the rate-controlling process for the interracial layer growth of brazing joints brazed with active composite filler materials, the thickness of brazing joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of AI203 particulate was studied. The experimental results indicate although there are Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth is t^2 as described by Fickian law for the joints brazed with conventional active filler metal. It also shows that the key factor affecting the interracial layer growth is the volume fraction of alumina in the composite filler material compared with the titanium weight fraction in the filler material.     

银基钎料在制造业中的研究进展

钎料的性能很大程度上决定了钎焊接头的质量和钎料的应用范畴.银基钎料作为一类非常重要的硬钎焊材料,其填缝能力优异,强度与黄铜、低碳钢接近,可钎焊除铝、镁合金等轻金属之外的所有金属材料.因此,银基钎料广泛应用于航空航天、超硬工具等制造领域,并且受到国内外钎焊界学者们的高度关注.然而,银基钎料的发展及应用过程中仍存在以下问题:第一,钎料中贵金属银含量偏高(一般高于45%),导致钎料使用成本高;第二,银基钎料挤压、轧制、拉拔等加工过程中不可避免地存在夹杂物,影响钎料的使用性能和连接质量;第三,有益金属或合金调控钎料及其连接性能的机制较为复杂,尚未完全研究清楚;第四,传统制备银基钎料的方法产能低下;第五,银基钎料在制造业领域的应用研究尚未见系统报道.国内外对于银基钎料钎焊性能及工程应用方面的研究主要集中于:(1)开发多种节银降银钎料,主要是有益元素调控银基钎料连接性能方面的研究;(2)改进钎料的传统加工方法,提出新的制造方法,如粉末电磁压制成形、钎焊过程中原位合成、快速凝固、镀覆扩散组合等;(3)研究杂质元素(C、Ca、S、Al、Fe、Bi、Pb、O、N 等)的影响;(4)银基钎料形态创新研究,如三明治复合钎料(中间为铜合金、两边为银钎料)、箔带钎料、镀锡银钎料等;(5)工程应用研究,银基钎料在航空航天、汽车制造、电力能源等工业领域起着不可替代的作用,但目前国内外仍缺乏系统阐述该方面研究的报道.因此,本文对近20年国内外有关银基钎料的研究报道进行了评述,重点讨论了合金元素对银基钎料性能的影响.首先对银基钎料研究现状进行详述,总结了Cu、Zn、Sn、Ga、In、Ni、Mn、Cd、Li、Ce、La、P、Si、Pr在银基钎料中的优缺点,归纳了杂质元素C、S、O、N、Ca、Al、Fe、Pb、Bi的恶化作用.其次对银基钎料在航空航天、汽车制造、电力能源、超硬工具、家用电器、眼镜行业等制造业中的应用研究进行详细介绍.最后提出银基钎料研究和应用中的不足,为银基钎料的深入系统研究及相关技术发展提供理论指导.     

Vacuum brazing of GH99 superalloy using graphene reinforced BNi-2 composite filler

A novel graphene reinforced BNi-2 composite filler was developed for brazing GH99 superalloy. The interfacial microstructure of brazed joints was analyzed by field emission scanning electron microscope and a transmission electron microscope. The effects of graphene addition on the microstructure evolution and mechanical properties of brazed joints were investigated, and the strengthening mechanism of graphene was analyzed. The results revealed that due to the addition of graphene, M₂₃(C,B)₆ compounds were synthesized in the γ solid solution and brittle boride precipitates near the brazing seam decreased. Graphene was effective in retarding solute atoms diffusion thus impeding the precipitation of borides. Furthermore, the low coefficient of thermal expansion (CTE) of graphene was conducive to relieve stress concentration of the brazed joints during the cooling process. The shear strengths of brazed joints were significantly improved by exerting the strengthening effect of graphene. The maximum shear strengths of the brazed joints were 410.4?MPa and 329.7?MPa at room temperature and 800?°C, respectively.     

Adaptation of the DCB test for determining fracture toughness of brazed joints in ceramic materials

We have developed a test, based on a modified applied moment double cantilever beam specimen, to measure the fracture toughness of brazed joints between ceramics and ceramics and metals. Evaluation of samples directly brazed with experimental brazing filler metals showed that the brazed interfaces were generally as tough as the ceramics alone, with toughness increasing proportionally to the toughness of the ceramics. Although the specimen and techniques have so far been used only for direct brazes (no surface pretreatment of the ceramic), we suggest that they would also be valid for joints involving metallization of the ceramics prior to brazing.     

Effects of gap filler and brazing temperature on fracture and fatigue of wide-gap brazed joints

The influence of gap filler content on the fracture, fatigue crack initiation and propagation of AISI 316 stainless steel wide-gap brazed with nickel-based filler metal has been investigated. The brazed joints were found to consist of eutectic, intermetallic compound and solid solution. The volume of solid solution was observed to depend on the gap filler content and brazing temperature. Tensile tests with extra small strain gauge bonded at the centre of the joints showed that the strength and elongation of the brazed joints increased with brazing temperature, and the addition of gap filler was able to improve the load-carrying capacity of the brazed joints only when the brazing temperature was high enough. Fatigue crack initiation and growth under displacement amplitude control were also carried out. Crack closure in the brazed joints was determined by means of back face strain on the compact tension specimen used. The introduction of gap filler was able to increase the fatigue and fracture resistance of the brazed joints when a suitable brazing temperature was used. Crack deflection, branching and uncracked ligament bridging behind the crack tip were observable along the crack paths. Experimental results showed that gap filler was able to enhance the crack closure caused by roughness and ligament bridging.     

钎缝间隙对316L不锈钢真空钎焊接头组织的影响

采用镍基钎料BNi2+40%BNi5对316L不锈钢进行真空钎焊。主要通过光学显微镜、电子探针显微分析仪、硬度计等研究了3种钎缝间隙下钎焊接头的显微组织、钎缝成分分布以及钎缝显微硬度。结果表明316L不锈钢的钎焊接头主要由固溶体、共晶组织及网状化合物组成,硼、硅是导致化合物相产生的主要合金元素;随着钎缝间隙的减小,钎焊接头中金属间化合物相的含量逐渐减小,当钎缝间隙为30μm时,接头组织基本为固溶体。     

Intermetallic compounds formed during brazing of titanium with aluminium filler metals

The effect of aluminium filler metal composition on the formation of AI-Ti intermetallic compounds was investigated in brazed aluminium-to-titanium (Al/Ti) joints and titanium-totitanium (Ti/Ti) joints. The clearance filling ability was also studied. In Ti/Ti joints, the thickness of the intermetallic compound layer was strongly dependent on the aluminium filler metal composition, whereas the clearance filling ability was independent of the composition. The maximum intermetallic compound layer thickness was observed in 99.99% highly pure aluminium filler metal; therefore all additional elements reduced the layer thickness. Above all, the addition of 0.8% Si greatly reduced the thickness. After brazing at 680° C for 3 min, the intermetallic compound formed by Al-0 to 0.8% Si filler metal was found to be of type Al₃Ti. Other compounds, of types Ti₉Al₂₃ and Ti₇Al₅Si₁₂, were also found in joints brazed by Al-3 to 10% Si filler metals. AI-0.8% Si filler metals maintained a higher joint strength than pure aluminium filler metal under brazing conditions of high temperature and long heating time. In Al/Ti joints, AI-Cu-Sn and AI-Cu-Ag filler metal mainly formed Al₃Ti, and Al-10Si-Mg filler metal mainly formed Ti₇Al₅Si₁₂ at the brazed interface of the titanium side after brazing at 600 to 620° C.     

Verhalten von Hochtemperatur-Lötverbindungen bei schwingender Belastung und erhöhten Temperaturen

Fatigue behaviour of High Temperature Brazed Joints tested at elevated temperatures Fatigue testing, on a systematic and statistical basis, was carried our on high temperature brazed joints produced in the base metal NiCr20TiAl joined with BNi-5 and BAu-4 filler metals. The single-stage tests were conducted with various temperatures of 500 and 700 °C. Microscopic examination of the fracture surfaces (SEM) yielded information about crack initiation and propagation and the fracture behaviour of the joints.