This paper presented the design of a new type of active filler metal Al-17.0Cu-8.0 Mg-xLa (x = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5 wt%) for vacuum brazing of composites 55 % SiCp/ZL102 and TC4. The effects of La on the microstructure and properties of brazing alloy and on the joint were studied. The results demonstrated as follows. The La element has a refining effect on the matrix structure of the brazing master alloy, which made the intergranular network of the structure clearer. High level of the element La resulted in the production of more oxides in the brazing alloy. The increase of La content led to the brazing alloy melting temperature decreased and the brazing seam thickness increased. A layer of tetragonal intermetallic compound tau 1(Ti7Al5Si12) phase with (Mohanavel et al., 2021; Wang et al., 2021; Zhu et al., 2018; Bhong et al., 2023; Egbo, 2021; Salonitis et al., 2010; Chen et al., 2023; Chen et al., 2024; Niu et al., 2019; Tariq et al., 2014; Du et al., 2016; Ma et al., 2015; Tang et al., 2021; Chong et al., 2021; Hekner et al., 2017; Yuan et al., 2023; Misra, 1991; Yan et al., 2022; Qiu et al., 2023; Dong et al., 2023; Li et al., 2023; Ma et al., 2020; Chen et al., 2024; Hong et al., 2023; Chen et al., 2024; Zhang et al., 2023; Zuo et al., 2020; Zhang et al., 2023; Zhao et al., 2022; Li et al., 2023; Xie et al., 2022) [1-31] crystal band axis was formed on the TC4 side. The intermetallic compound at the brazing seam gradually extended to the composite side with the increase of La content. Needle-like structure was transformed into massive structure with increased La content, and the width of the brazing seam increased. The shear strength reached the highest value of 88.0 MPa at 2.0 % La. The joint broke at the brazing seam, and the fracture behavior belongs to brittle fracture.

Paste-type brazing materials have advantages such as adjusting the complexity of the parts to be soldered, easy storage and production in certain quantities. They can be used for brazing heat exchangers, liquid tanks and corrosion resistant parts. In this work, the microstructures and thermal behaviors of Al–Si–Cu–Ni brazing materials with different contents were investigated, and the effect of brazing process on the microstructural evolution and mechanical properties of brazed joints produced under nitrogen-filled environment was examined. It was found that the melting temperature of brazing material Al–5Si–20.5Cu–2Ni were ranged from 512.86 to 549.37 °C. The microstructure of Al–5Si–20.5Cu–2Ni consisted of α-Al solid solution, CuAl2 intermetallic compounds, the Al–Si–Cu phase, and some fine irregular Si particles in a homogenous manner. The microstructure of the brazed joints was uniformly formed during the brazing condition of 580 °C for 20 min, and the shear strength of the joints reached 41.76 MPa.

A total of 55% SiC p /ZL102 composites were surface metalized by electroless nickel plating. The Al-17Cu-8 Mg-2Ni as-cast brazing alloy was prepared into foil-like by melt spinning machine through ultra-cold thin strip system. The obtained foil-like brazing alloy has better flexibility, more uniform element distribution, and higher free energy than the as-cast brazing alloy. The 55% SiC p /ZL102 composites after nickel plating were brazed by different brazing processes in the air. The Ni–P coating effectively inhibited the formation of alumina film on the composite surface. However, the presence of an oxide layer on the foil filler caused a negative effect on the Ni–P coating and hindered the diffusion between elements. SiC, Ni 2 Al 3 , and other phases were detected in the joint port. The characteristic morphologies such as furrows and massive particles indicated that the fracture behavior is brittle fracture. The maximum shear strength of the joint was 88.31 MPa at 590 °C.

High-volume-fraction aluminum matrix composites reinforced with SiC particles (SiCp/Al MMCs) have been widely used in aerospace and other fields due to their excellent properties. However, joining high-volume-fraction SiCp/Al MMCs is challenging. In this work, an efficient and high-strength method was developed to join high-volume fraction SiCp/Al MMCs. SiCp/ZL102 composites (55 vol.

In this work, Al-17.0Cu-8.0 Mg-1.5Ni an active brazing alloy is designed for brazing third-generation electronic packaging material 55 vol.

High-volume-fraction aluminum matrix composites reinforced with SiC particles (SiC p /Al MMCs) have been widely used in aerospace and other fields due to their excellent properties. However, joining high-volume-fraction SiC p /Al MMCs is challenging. In this work, an efficient and high-strength method was developed to join high-volume fraction SiC p /Al MMCs. SiC p /ZL102 composites (55 vol.%) were brazed by Al-17.0Cu-8.0 Mg-1.5Ni filler metal in atmospheric environment. Compared to as-cast filler metal, the foil-like filler metal prepared by melt-spinning has finer grains and superior diffusion performance. The microstructure, shear strength, and fracture morphology of the joint were investigated. The brazed joint at 580 °C for 30 min exhibited a maximum shear strength of 92 ± 2 MPa, and the foil-like filler metal had optimal bonding performance with the base material. Meanwhile, the elements between the filler metal and base material interdiffused and metallurgical reacted. As a result, the oxide films on the surface of filler metal and of SiC p /ZL102 composites were broken; furthermore, Al 2 MgO 4 and MgO were formed in the joint interface based on the redox reaction. The fracture type of brazed joint was a mixed ductile–brittle fracture.

Hexagonal boron nitride (h-BN) has a promising application in the field of electronic devices due to its many unique properties, but the nucleation mechanism of h-BN on transition metal surfaces in chemical vapor deposition (CVD) experiments is still unclear. Here, we systematically investigated the formation energy and stability of h-BN clusters on 10 kinds of transition metal surfaces using density functional theory (DFT) calculations. The results show that h-BN clusters on different metal substrates may undergo the transition to the most stable structure at a critical size, but the critical size is different for different metal substrates. For the BN clusters on Ag(111) surface, the ground-state structures are chain-like and ring-shaped configurations at n < 4 and 4 < n < 11, respectively, then the honeycomb becomes the most stable one when the size of BN clusters increases to n = 12. The most stable structures for BN clusters on Cu, Pd and Co surfaces change from chain-like to sp2 honeycomb at the critical size of n = 8, 7 and 8, respectively. Thereafter, the honeycomb structure becomes the most energetically favourable one and continues to grow until it covers the entire substrate. Efficient charge transfer from underlying metals and highly symmetric structures are key factors for the stabilization of BN clusters. The study of BN nucleation on an atomic scale is helpful to improve experimental conditions and design experiments for the preparation of h-BN films or other two-dimensional (2D) materials.

SiC-particulate-reinforced aluminum matrix composites (SiCp/Al MMCs) are widely used in the aerospace field due to their high specific stiffness and strength, low thermal expansion coefficient, and good radiation resistance. In the process of application and promotion, there is a connection problem between the aluminum matrix composites and electronic glass. In this work, the lead-free SiO2-B2O3-Na2O glass filler was used to seal 65 vol.% SiCp/ZL102 composites and DM305 electronic glass in an atmospheric environment. The effects of the sealing temperature on the properties of the joints were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Additionally, the causes of defects and the fracture mechanisms of the joints were analyzed. The results showed that the glass filler and base material were connected through a dual mechanism of an Al, Na, Si, and O element diffusion reaction and a mechanical occlusion. At a sealing temperature of 540 °C and a holding time of 30 min, the joint interface was dense and crack-free. Meanwhile, the average shear strength reached 13.0 MPa, and the leakage rate of air tightness was 1 × 10−9 Pa·m3/s. The brittle fracture features were revealed by the step-like morphology of the fracture, which originated from the brazing seam and propagated into the pore. The crack gradually propagated into the base material on both sides as the fracture area expanded, ultimately resulting in a fracture.

In this paper, a dissimilar material consisting of 55% SiCp/ZL102 composites and TC4 titanium alloy was brazed using Al-8.0 Mg-17.0Cu-1.0Ti foil-like brazing alloy manufactured by rapid solidification technology. Brazing was completed in a vacuum of 1.0 x 10-4 Pa. Si element from Al composites accumulated at the interface of TC4 titanium alloy to form Ti7Al5Si12 intermetallic compound layer. The intermetallic compound alpha 2(TiAl3) grew perpendicular to the brazing seam below 590 degrees C. The alpha 2(TiAl3) intermetallic compound grown into long strips at 590 degrees C. The strip structure had a bonding interface in the form of pinning at a certain angle. The brazing interface was continuous and dense, without defects and exhibited good bonding performance. The shear strength of the brazed joint reached 98.01 MPa at 590 degrees C for 30 min, and the gas tightness was 1.0 x 10-10 Pa m3/s. The brazed joint failed in filler metal due to ductile-brittle mixed fracture mechanism, which resulted in shear lips, parabolic dimples, and furrows in the fracture surface.

用自制Sn-Cu-In-xCe钎料进行镀Ni高硅铝合金与覆Ag钠钙玻璃的真空钎焊,研究接头界面组织及断裂机制,分析稀土元素Ce及钎焊工艺对接头剪切强度的影响.结果表明:添加适量稀土元素Ce可增强接头剪切强度,当Ce的质量分数为0.2％时,增强效果最佳;随钎焊温度升高和保温时间延长,接头剪切强度先升后降,当钎焊工艺为280℃、25 min时,接头剪切强度达最大值(21.13 MPa),此时接头界面结构为高硅铝合金/Ni/(Ni+Cu)6Sn5/Cu6Sn5+Ag3Sn/Ag/钠钙玻璃;剪切试验接头断裂于钎料/Ag层界面,以脆性断裂为主的脆韧混合断裂机制.

为了研究不同镀镍时间对铝基复合材料化学镀镍的影响,采用化学镀镍方法对SiCp/6063A1复合材料进行表面处理.通过金相显微等手段研究SiCp/6063Al复合材料镀层表面微观形貌、镀层厚度以及化学镀镍层与基体材料的结合力.研究结果表明:化学镀镍20min后,复合材料表面的胞状组织结构致密均匀,没有孔隙;随着对铝基复合材料化学镀镍时间的增加,镀镍层厚度增加、胞状组织排列愈加紧密,并且胞状组织分布均匀且逐渐增大.通过对30min时间内化学镀镍层厚度的分析认为镀层厚度和镀镍时间表现为幂指函数关系;通过镀镍层划痕试验,表明镍层与基体结合良好.

本研究在大气环境下将PbO-ZnO-SiO2系非晶玻璃粉末和PbTiO3晶体粉末等比例混合均匀制得了复合玻璃钎料,实现了高体积分数SiCp/6063Al复合材料和DM305玻璃之间的连接.结果表明:当封接温度为480℃,保温30 min,复合玻璃钎料完成了预氧化后的复合材料与DM305玻璃之间的连接,接头无裂纹、气孔等缺陷,剪切强度为7.55 MPa,气密性为1×10-8 Pa·cm3/s,符合使用要求.在封接过程中,复合玻璃钎料与母材的氧化膜相溶,在复合材料一侧出现了Al元素的扩散现象.

In this age of human civilization, there is a need for more efficient, cleaner, and renewable energy as opposed to that provided by nonrenewable sources such as coal and oil. In this sense, hydrogen energy has been proven to be a better choice. In this paper, a portable graphite crucible metal smelting furnace was used to prepare ten multi-element aluminum alloy ingots with different components. The microstructure and phase composition of the ingots and reaction products were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The reaction was carried out in a constant temperature water bath furnace at 60 °C, and the hydrogen production performance of the multi-element aluminum alloys in different proportions was compared by the drainage gas collection method. The experimental results show that the as-cast microstructure of Al–Ga–In–Sn aluminum alloy is composed of a solid solution of Al and part of Ga, and a second phase of In3Sn. After the hydrolysis reaction, the products were dried at 150 °C and then analyzed by XRD. The products were mainly composed of AlOOH and In3Sn. Alloys with different compositions react at the same hydrolysis temperature, and the hydrogen production performance is related to the ratio of low-melting-point metal elements. By comparing two different ratios of Ga–In–Sn (GIS), the hydrogen production capacity and production rate when the ratio is 6:3:1 are generally higher than those when the ratio is 7:2:1. The second phase content affects the hydrogen production performance.

SiC particulate reinforced aluminum metal matrix composites (SiCp/Al MMCs) are characterized by controllable thermal expansion, high thermal conductivity and lightness. These properties, in fact, define the new promotional material in areas and industries such as the aerospace, automotive and electrocommunication industries. However, the poor weldability of this material becomes its key problem for large-scale applications. Sintering bonding technology was developed to join SiCp/Al MMCs. Cu nanoparticles and liquid Ga were employed as self-fluxing filler metal in air under joining temperatures ranging from 400 °C to 500 °C, with soaking time of 2 h and pressure of 3 MPa. The mechanical properties, microstructure and gas tightness of the joint were investigated. The microstructure analysis demonstrated that the joint was achieved by metallurgical bonding at contact interface, and the sintered layer was composed of polycrystals. The distribution of Ga was quite homogenous in both of sintered layer and joint area. The maximum level of joint shear strength of 56.2 MPa has been obtained at bonding temperature of 450 °C. The specimens sintering bonded in temperature range of 440 °C to 460 °C had qualified gas tightness during the service, which can remain 10−10 Pa·m3/s.

Using Ti foil with thickness of 0.1 mm as the interlayer, SiCp/6061-T6Al MMCs was welded by employing low-power laser-TIG hybrid welding. After welding experiment, the macro morphology, microstructure, phase, resistivity, tensile strength and fracture morphology of the joint were analyzed. The results show that laser power has significant influence on the formability of welding seam. Ti foil can basically suppress the formation of needle-like Al4C3 in weld seam. Meanwhile, some new phases such as TiC reinforcement phase and strip-like TiAl3 generate in welding seam. The microstructures of weld zone and fusion zone are equiaxed crystal and columnar crystal, respectively. The microstructure in heat-affected zone does not change obviously. The joint resistivity increases with the increasing of laser power and the value of joint resistivity is significantly higher than that in base material. The joint tensile strength achieves 196.98 MPa, which is equal to 54.71% of base material, when laser power of 554 W is applied. There are almost no pores in joint fracture and the second phase particle in dimple is mainly composed of TiC. The joint displays the characteristics of brittle-ductile mixed fracture which is dominated by brittle fracture.

用自主研发的In-48Sn-1Ag新型无铅钎料对镀镍后体积分数为15％的SiCp/6063Al复合材料进行真空钎焊.钎焊温度为180、185、190、195、200℃,保温时间为15、20、25、30 min.通过扫描电镜(SEM)、能谱仪(EDS)、物相分析(XRD)及抗剪切强度测试等手段对钎料合金及钎焊接头的组织和性能进行分析.结果表明:钎料合金中主要存在In?Sn4、AgIn2、In3Sn相.接头剪切强度随钎焊温度和保温时间增加先增后降,当钎焊温度为190℃,保温时间为20 min时,钎焊接头的剪切强度最高,达16.61 MPa,此时钎料与复合材料表面的镍层结合最好,断口形貌以脆性断裂为主的脆-韧共存混合断裂.

用PbO-SiO2-Al2O3系复合片状玻璃钎料,在大气环境下实现SiCp/6063Al复合材料与DM305电子玻璃的连接.用XRD、SEM、EDS和DSC等研究不同保温时间和温度下对焊接接头的影响.结果表明:在一定范围内焊接温度升高和保温时间延长可提高接头强度.SiCp/6063Al复合材料与DM305电子玻璃在钎焊温度为480℃保温30 min时,获得最大剪切强度为7.16 MPa的接头,且满足气密性使用要求.钎焊过程中,钎料中的元素能扩散到母材中,提高接头强度.

用Al-12Si-20Cu-1Mg-1Ni合金为钎料,对质量分数为55％的SiCp/ZL102复合材料进行真空钎焊,钎焊温度为560、570、580、590、600℃,保温时间为30min.对不同温度下焊接接头的显微组织、维氏硬度、抗剪切强度、断口形貌进行分析.结果表明:随着钎焊温度增加,接头的剪切强度先增后降,焊接温度为590℃时,钎料与母材间的结合最好,焊缝中心与母材处的硬度值最大,为250.5HV和161.79HV,同时焊接接头的抗剪切强度达最大值60.4MPa,焊接接头呈脆性断裂和韧性断裂共存的混合断裂形貌.

In this paper, the effect of different surface pretreatment method on properties of vacuum brazed joint of AlSi50 alloy was investigated. The surface pretreatment methods of specimen before brazing include sanding, NaOH corrosion, HCl corrosion, H2SO4 corrosion and nickel plating. The experimental results indicate that the width of brazing joint varies with different surface pretreatment methods. The joint with sanding pretreatment, has the largest brazing seam width of 20 μm. Meanwhile, joint with H2SO4 corrosion has the narrowest brazing seam width. The brazing filler metal can wet and spread on different pretreated specimen very well. Spectrum analysis indicates that nickel-plate on AlSi50 surface, can interact with brazing filler metal, which increases mechanical property of brazing joint. For brazing of AlSi50 alloy, the optimal pretreatment method is nickel plating. After nickel plating pretreatment, brazing joint has the maximum shear strength 82.05 MPa by using brazing filler metal Al52-Cu33-Mg12-Ni3 and following technological parameters: brazing temperature 580 ℃, soaking time 30 min and pressure 3 MPa.