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Li M.,Harbin Institute of Technology | Yang M.,Harbin Institute of Technology | Kim J.,Jeonnam Provincial College
Materials Letters | Year: 2012

The growth orientations of Cu6Sn5 grains formed at a Sn3.5Ag/polycrystalline Cu interface were investigated. Similar as reported on Cu single crystals, strong textures in Cu6Sn5 layers can also form on polycrystalline Cu, but the texture formation mechanisms differ. The texture formation on polycrystalline Cu occurs during the ripening growth and results from the differences in stability of the interfacial grains with various orientations at different temperatures. A reaction temperature of 240 °C causes the Cu6Sn5 layer to form [0001] texture in the direction normal to the substrate, and a special morphology of interfacial Cu6Sn5 grains can be formed on this layer to reinforce joint properties. © 2011 Elsevier B.V. Source


The adhesion between zinc borate-containing rubber compounds and brass-plated steel cords was studied to understand the role of zinc borate as an adhesion promoter. No improvement in adhesion after cure was shown with loading of zinc borate in the range 0.5-2 phr, while enhancement of adhesion retention after humidity aging was observed with loading of zinc borate in the range 0.5-2 phr. The adhesion interphase between the brass-plated steel cord and the rubber compound subjected to humidity aging treatment showed, using AES, a stabilized depth profile by a moderate loading of zinc borate, resulting in enhancement of adhesion retention. For the high loading of zinc borate, copper sulfide layer and zinc oxide layer grew excessively in the adhesion interphase under humidity aging. © 2010 Koninklijke Brill NV, Leiden. Source


Yang M.,Harbin Institute of Technology | Li M.,Harbin Institute of Technology | Wang L.,China National Electrical Apparatus Research Institute | Fu Y.,China National Electrical Apparatus Research Institute | And 2 more authors.
Materials Letters | Year: 2011

The growth behavior of Cu6Sn5 grains formed at an Sn3.5Ag/Cu interface was investigated. During soldering, Cu6Sn 5 grains formed at the interface, showing a flattened ovoid shape. During solidification, Cu precipitated from molten solder in the form of Cu 6Sn5, forming faceted surfaces on existing interfacial grains. The interfacial Cu6Sn5 morphology was unrelated to its crystal orientation, which was primarily dependent on reaction temperature. A reaction temperature of 240 °C led to an increase in (002) growth and a decrease in (101) growth with time. However, the (002) plane peak was not detected in the interfacial grains formed at a higher reaction temperature (280 °C). © 2011 Elsevier B.V. All rights reserved. Source


Three brass-plated steel cords with different copper contents from 51.4 to 75.5% were prepared and their adhesion properties to rubber compound were examined. Adhesion properties improved with the decrease in the copper content. The high adhesion of brass-plated steel cord with low copper content to the rubber was obtained after cure and after hostile aging treatments. The stability against humidity aging and the cause for the high adhesion of the brass-plated steel cord with low copper content were discussed in conjunction with the formation and growth of adhesion interphase determined by Auger electron spectroscopy depth profile. The excellent adhesion stability of brass-plated cord with low copper content can be explained by the suppression of the excessive growth of copper sulfide and the inhibition of dezincification due to the low copper content. © 2014 Taylor & Francis. Source


Xiao Y.,Harbin Institute of Technology | Ji H.,Harbin Institute of Technology | Li M.,Harbin Institute of Technology | Kim J.,Jeonnam Provincial College
Materials and Design | Year: 2013

Ultrasound-assisted brazing of Cu/Al dissimilar metals was performed using a Zn-3Al filler metal. The effects of brazing temperature on the microstructure and mechanical properties of Cu/Al joints were investigated. Results showed that excellent metallurgic bonding could be obtained in the fluxless brazed Cu/Al joints with the assistance of ultrasonic vibration. In the joint brazed at 400°C, the filler metal layer showed a non-uniform microstructure and a thick CuZn5 IMC layer was found on the Cu interface. Increasing the brazing temperature to 440°C, however, leaded to a refined and dispersed microstructure of the filler metal layer and to a thin Al4.2Cu3.2Zn0.7 serrate structure in the Cu interfacial IMC layer. Further increasing the brazing temperature to 480°C resulted in the coarsening of the filler metal and the significantly growth of the Al4.2Cu3.2Zn0.7 IMC layer into a dendrite structure. Nanoindentation tests showed that the hardness of the Al4.2Cu3.2Zn0.7 and CuZn5 phase was 11.4 and 4.65GPa, respectively. Tensile strength tests showed that all the Cu/Al joints were failed in the Cu interfacial regions. The joint brazed at 440°C exhibited the highest tensile strength of 78.93MPa. © 2013 Elsevier Ltd. Source

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