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1.
This research sought to improve the properties of SAC305 solder joints by the addition of 1 and 2 wt.% Bi. The effects of bismuth doping on the microstructure, thermal properties, and mechanical performance of the SAC305-xBi/Cu solder joints were investigated. Bi-doping modified the microstructure of the solder joints by refining the primary β-Sn and eutectic phases. Bi-doping below 2 wt.% dissolved in the β-Sn matrix and formed a solid solution, whereas Bi additions equal to or greater than 2 wt.% formed Bi precipitates in the β-Sn matrix. Solid solution strengthening and precipitation strengthening mechanisms in the β-Sn matrix increased the ultimate tensile strength and microhardness of the alloy from 35.7 MPa and 12.6 HV to 55.3 MPa and 20.8 HV, respectively, but elongation decreased from 24.6% to 16.1%. The fracture surface of a solder joint containing 2 wt.% Bi was typical of a brittle failure rather than a ductile failure. The interfacial layer of all solder joints comprised two parallel IMC layers: a layer of Cu6Sn5 and a layer of Cu3Sn. The interfacial layer was thinner and the shear strength was greater in SAC305-xBi/Cu joints than in SAC305/Cu solder joints. Therefore, small addition of Bi refined microstructure, reduced melting temperature and improved the mechanical performance of SAC305/Cu solder joints.  相似文献   
2.
The as-cast microstructure, element segregation and solidification behavior of a multi-alloyed superalloy ЭК151 have been investigated. The results show that the severe element segregation leads to the complicated precipitations at the inter-dendritic region, including η-Ni_3(Ti, Nb), eutectic(γ + γ') and Laves, which shows the characteristics of both Ti, Al-strengthened and Nb-strengthened alloys. Differential thermal analysis, heating and quenching tests reveal the solidification sequence as follows: Liquids →γ matrix →(Nb, Ti)C →η-Ni 3(Ti, Nb) →eutectic( γ+γ') → Laves. The melting points are between 1250 and 1260 °C for(Nb, Ti)C, between 1200 and 1210 °C for η phase, between 1180 and 1190 °C for eutectic(γ+γ') and Laves. γ' initially precipitates from matrix at 1150 °C and achieves the maximum precipitation at 1130 °C. According to the microstructure evolution captured during solidification and composition analysis by an energy dispersive spectrometer and electron probe microanalyzer,(Nb, Ti)/Al ratio is put forward to explain the formation of η-Ni_3(Ti, Nb) and eutectic( γ+γ'). The solidification of γ matrix increased the Nb, Ti concentration in the residual liquids, so the high(Nb, Ti)/Al ratio would result in the formation of η-Ni_3(Ti, Nb); the precipitation of the phase consumed Nb and Ti and decreased the(Nb, Ti)/Al ratio in the liquid, which led to the precipitation of eutectic(γ + γ'). Laves formed by the sides of η-Ni_3(Ti, Nb) and in front of the eutectic( γ + γ') after Al, Ti were further depleted by the two phases and Cr, Co, Mo were rejected to liquids.  相似文献   
3.
在Zn20Sn高温无铅钎料合金中添加0.1%RE及0.2%~0.8%Ni(质量分数,下同),研究了RE及Ni对钎料合金显微组织及性能的影响。结果表明,在Zn20Sn中同时添加0.1%RE及0.2%~0.8%Ni后,钎料合金的固相线变化不大,而液相线温度降低;RE及Ni对钎料合金的润湿性能及显微硬度有明显的影响,当RE为0.1%、Ni为0.4%时,钎料合金的润湿性能最好、显微硬度最高;随着RE及Ni的添加,在钎料合金中形成了含Ni金属间化合物,且随着Ni含量的提高,金属间化合物的形状、钎料合金的组织结构发生显著变化。  相似文献   
4.
To improve the microstructure and properties of ZrB2-SiC (ZrB2-30?vol%SiC, Z7S3) coatings, a facile synthesis route involving induction plasma spheroidization (IPS) has been proposed, and the morphologies, particle size distributions, and phase compositions of the feedstock powders were analysed by scanning electron microscopy and focused ion beam techniques. The obtained results showed that the surfaces of the produced powders contained eutectic-like and granular zones. Owing to the existence of a temperature gradient, the internal microstructure of the IPS-treated powder exhibited a three-layered structure consisting of a ′surface shell′, a ′transition layer′, and a ′porous core′. Additionally, the properties of the IPS-treated samples were compared with those of the spray-dried (SD) powders. The former exhibited good plastic deformation properties, and their single splats contained flattened structures, while the single splats of the SD powder melted only partially retaining some of their original characteristics.  相似文献   
5.
A novel interconnection technology based on a 52InSn solder was developed for flexible display applications. The display industry is currently trying to develop a flexible display, and one of the crucial technologies for the implementation of a flexible display is to reduce the bonding process temperature to less than 150°C. InSn solder interconnection technology is proposed herein to reduce the electrical contact resistance and concurrently achieve a process temperature of less than 150°C. A solder bump maker (SBM) and fluxing underfill were developed for these purposes. SBM is a novel bumping material, and it is a mixture of a resin system and InSn solder powder. A maskless screen printing process was also developed using an SBM to reduce the cost of the bumping process. Fluxing underfill plays the role of a flux and an underfill concurrently to simplify the bonding process compared to a conventional flip‐chip bonding using a capillary underfill material. Using an SBM and fluxing underfill, a 20 μm pitch InSn solder SoP array on a glass substrate was successfully formed using a maskless screen printing process, and two glass substrates were bonded at 130°C.  相似文献   
6.
对比研究了SAC305、SAC0307、SAC0307X共3种无铅钎料在不同环境温度和加载速率下的力学性能。结果表明,合金元素Ni、P等的添加能有效改善低Ag钎料的拉伸力学性能,但对钎料韧性提高有限;低Ag钎料SAC0307在55℃下的强度和韧性均低于SAC305钎料,而在85℃其韧性优于SAC305钎料。在55℃和85℃条件下,钎料合金拉伸力学性能均显著下降,在加载速率20 mm/min和55℃条件下,SAC305综合力学性能更有优势;而在85℃,低Ag无铅钎料SAC0307具备优势,因此低银无铅钎料应用需要进一步改善其在40~60℃范围的综合力学性能。  相似文献   
7.
Recently, we have witnessed the gradual miniaturization of electronic devices. In miniaturized devices, flip‐chip bonding has become a necessity over other bonding methods. For the electrical connections in miniaturized devices, fine‐pitch solder bumping has been widely studied. In this study, high‐volume solder‐on‐pad (HV‐SoP) technology was developed using a novel maskless printing method. For the new SoP process, we used a special material called a solder bump maker (SBM). Using an SBM, which consists of resin and solder powder, uniform bumps can easily be made without a mask. To optimize the height of solder bumps, various conditions such as the mask design, oxygen concentration, and processing method are controlled. In this study, a double printing method, which is a modification of a general single printing method, is suggested. The average, maximum, and minimum obtained heights of solder bumps are 28.3 μm, 31.7 μm, and 26.3 μm, respectively. It is expected that the HV‐SoP process will reduce the costs for solder bumping and will be used for electrical interconnections in fine‐pitch flip‐chip bonding.  相似文献   
8.
Thermoelectric materials have drawn widespread attention because they can enable the direct conversion between electric and thermal energy. Over the years, different materials such as skutterudites, clathrates, intermetallic alloys, eutectic alloys, chalcogenides have been explored for Thermoelectric (TE) applications. Amongst the eutectic alloys, the Bi-Ga-Te system exhibits promising potential as a TE material. Accordingly, in this study, we performed the thermodynamic optimization and critical evaluation of binary Bi–Ga, Bi–Te, Ga–Te, and ternary Bi-Ga-Te systems using the CALPHAD method. It is observed that the Ga–Te system shows asymmetric liquid solution properties with strong negative enthalpy of mixing, whereas the Bi–Te liquid exhibits the symmetric regular solution behavior. Moreover, the Bi–Ga liquid solution has a positive enthalpy of mixing. Therefore, Modified Quasichemical Model (MQM) using pair approximation was utilized to describe the diversified thermodynamic properties of liquid solution in sub-binaries by taking into account the Short-Range Ordering (SRO). By merging the binary optimization results with a proper interpolation method, the liquid solution properties and phase diagram information in the Bi-Ga-Te ternary system were also reproduced successfully without any adjustable ternary parameter. Several ternary eutectic compositions were suggested for designing TE alloy with enhanced properties using the developed database.  相似文献   
9.
锡铅焊料中的杂质元素对焊点的抗氧化性、润湿性、扩展面积有重要影响,因此对其进行测定意义重大。采用硝酸、氢氟酸溶解样品,选择H2动态反应池模式测定Fe,标准模式测定Al、P、Cu、Zn、As、Cd、Ag、Sb、Au、Bi,同时以Sc校正Al、P、Fe、Cu,以Cs校正Zn、As、Ag、Cd,以Tl校正Sb、Au、Bi,实现了电感耦合等离子体质谱法(ICP-MS)对锡铅焊料中这11种杂质元素含量的测定。在优化的实验条件下,11种杂质元素校准曲线的相关系数均大于0.999,方法的检出限在0.002~0.80μg/g范围内,测定下限在0.007~2.73μg/g范围内。用建立的实验方法测定锡铅焊料样品中Al、P、Fe、Cu、Zn、As、Cd、Ag、Sb、Au、Bi,平行测定11次结果的相对标准偏差(RSD)为0.85%~3.5%,加标回收率为90%~110%。将实验方法应用于锡铅焊料标准物质YT9302中Al、Fe、Cu、Zn、As、Sb、Bi共7种杂质元素的测定,结果与认定值一致。  相似文献   
10.
If due to the market analysis a company makes the decision for the production of a new product by application of soldering and special the soldering with temporarily liquid solder, this one is then made specifically after that the company specific construction and production preparation. Either the decision for soldering is technically and/or economically well‐founded or she is even unavoidable by so‐called mixed material connections in the assemblies. This hybrid design finds application increasing today. In the contribution on hand the analysis and assessment of the soldering theory and practice is carried out under the point of view of the possible production of “ideal soldered connections” and “optimal soldered connections”.  相似文献   
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