Cu/Sn couples, prepared by sequentially electroplating Cu and Sn layers on metallized Si wafers, were employed to study the microstructures, phases and the growth kinetics of Cu-Sn intermediate phases, when electropla...Cu/Sn couples, prepared by sequentially electroplating Cu and Sn layers on metallized Si wafers, were employed to study the microstructures, phases and the growth kinetics of Cu-Sn intermediate phases, when electroplated Cu/Sn couples were aged at room temperature or annealed at temperatures from 373 K to 498 K for various time. Only Cu6Sn5 formed in aged couples or couples annealed at temperature below 398 K. The Cu6Sn5 layer was continuous, but not uniform, with protrusions extending into the Sn matrix. When Cu/Sn couples were annealed at temperatures from 423 K to 498 K, two continuous and uniform Cn6Sn5/Cu3Sn layers formed within the reaction region between Sn and Cu. There were many voids near the Cu3Sn/Cu interface and within the Cu3Sn layer. Cu6Sn5 and Cu3Sn formations both follow parabolic growth kinetics with activation energies of 41.4 kJ/mol for Cu6Sn5 and 90.4 kJ/mol for Cu3Sn, respectively.展开更多
The mechanical and diffusion properties of bcc Ti−Nb−Zr−Sn alloys in the Ti-rich corner were analyzed through a high-throughput method with the combination of nanoindentation and diffusion couple techniques.Nine group...The mechanical and diffusion properties of bcc Ti−Nb−Zr−Sn alloys in the Ti-rich corner were analyzed through a high-throughput method with the combination of nanoindentation and diffusion couple techniques.Nine groups of quaternary Ti−Nb−Zr−Sn diffusion couples were prepared after annealing at 1273 K for 25 h.The composition-dependent mechanical properties were determined by nanoindentation and electron probe microanalysis(EPMA)techniques.Moreover,the corresponding interdiffusion coefficients were confirmed from the composition gradients of the quaternary diffusion couples using a pragmatic numerical inverse method.A composition-dependent database on the mechanical and diffusion properties was utilized to discuss the processability during the hot working.The results reveal that the solute elements Nb and Sn are strictly controlled to increase the hardness and wear resistance of Ti−Nb−Zr−Sn alloys,and the additional element Zr is mainly useful to improve the processability during the hot working.展开更多
By means of sn-function expansion method and cn-function expansion method, several kinds of explicit solutions to the coupled KdV equations with variable coefficients are obtained, which include three sets of periodic...By means of sn-function expansion method and cn-function expansion method, several kinds of explicit solutions to the coupled KdV equations with variable coefficients are obtained, which include three sets of periodic wave-like solutions. These solutions degenerate to solitary wave-like solutions at a certain limit. Some new solutions are presented.展开更多
基金the Natural Sciences and Engineering Research Council (NSERC) of Canada and Micralyne, Inc. for providing research funding and Si substrates for electroplating (Micralyne)
文摘Cu/Sn couples, prepared by sequentially electroplating Cu and Sn layers on metallized Si wafers, were employed to study the microstructures, phases and the growth kinetics of Cu-Sn intermediate phases, when electroplated Cu/Sn couples were aged at room temperature or annealed at temperatures from 373 K to 498 K for various time. Only Cu6Sn5 formed in aged couples or couples annealed at temperature below 398 K. The Cu6Sn5 layer was continuous, but not uniform, with protrusions extending into the Sn matrix. When Cu/Sn couples were annealed at temperatures from 423 K to 498 K, two continuous and uniform Cn6Sn5/Cu3Sn layers formed within the reaction region between Sn and Cu. There were many voids near the Cu3Sn/Cu interface and within the Cu3Sn layer. Cu6Sn5 and Cu3Sn formations both follow parabolic growth kinetics with activation energies of 41.4 kJ/mol for Cu6Sn5 and 90.4 kJ/mol for Cu3Sn, respectively.
基金supported by the National Natural Science Foundation for Youth of China (No. 51701083)the Guangzhou Science and Technology Association Young Talent Lifting Project, China (No. X20210201054)+2 种基金the Guangdong Provincial Natural Science Foundation for Doctoral Research Project, China (No. 2017A030310519)the Open Fund of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials, China (No. HKDNM201903)financial support from the Guangdong Basic and Applied Basic Research Foundation, China (No. 2019A1515110095)。
文摘The mechanical and diffusion properties of bcc Ti−Nb−Zr−Sn alloys in the Ti-rich corner were analyzed through a high-throughput method with the combination of nanoindentation and diffusion couple techniques.Nine groups of quaternary Ti−Nb−Zr−Sn diffusion couples were prepared after annealing at 1273 K for 25 h.The composition-dependent mechanical properties were determined by nanoindentation and electron probe microanalysis(EPMA)techniques.Moreover,the corresponding interdiffusion coefficients were confirmed from the composition gradients of the quaternary diffusion couples using a pragmatic numerical inverse method.A composition-dependent database on the mechanical and diffusion properties was utilized to discuss the processability during the hot working.The results reveal that the solute elements Nb and Sn are strictly controlled to increase the hardness and wear resistance of Ti−Nb−Zr−Sn alloys,and the additional element Zr is mainly useful to improve the processability during the hot working.
文摘By means of sn-function expansion method and cn-function expansion method, several kinds of explicit solutions to the coupled KdV equations with variable coefficients are obtained, which include three sets of periodic wave-like solutions. These solutions degenerate to solitary wave-like solutions at a certain limit. Some new solutions are presented.
