Commercial hydrogen production involves the development of efficient hydrogen evolution reaction catalysts.Herein,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a ...Commercial hydrogen production involves the development of efficient hydrogen evolution reaction catalysts.Herein,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a self-supporting copper-silver(CuAg)catalyst.The gust of Ag atoms with larger atomic sizes caused a tensile strain in the Cu matrix.Meanwhile,the chemical-potential difference induced electron transfer from Cu to Ag,and the two factors jointly led to the upshift of Cu d-band and improved the catalytic activity.Consequently,the CuAg electrode exhibited a high turnover frequency(12 times that of pure Cu),a low overpotential at high current density(superior to platinum foil),and high durability(1.57%decay over 180 h).Our work demonstrates that FSP is a powerful method for preparing self-supporting catalysts of immiscible alloys with high catalytic performance.展开更多
A 3-D finite element model is developed to predict the temperature field and thermally induced residual stress and distortion in laser＋GMAW hybrid welding of 6061-T6 aluminum alloy T-joint. And the characteristics of...A 3-D finite element model is developed to predict the temperature field and thermally induced residual stress and distortion in laser＋GMAW hybrid welding of 6061-T6 aluminum alloy T-joint. And the characteristics of residual stress distribution and deformation are numerically investigated. In the simulation, the heat source model takes into account the effect of joint geometric shape and welding torch slant on the heat flux distribution and a sequentially coupled thermo-mechanical method is used. The calculated results show that higher residual stress is distributed in and surround the weld zone. Its peak value is very close to the yield strength of base metal. Besides, a large deformation appears in the middle and rear part of the weldment.展开更多
基金supported by the National Natural Science Foundation of China (Nos.51871160 and 52101266)the Natural Science Foundation of Hefei Grant (No.2022046)。
文摘Commercial hydrogen production involves the development of efficient hydrogen evolution reaction catalysts.Herein,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a self-supporting copper-silver(CuAg)catalyst.The gust of Ag atoms with larger atomic sizes caused a tensile strain in the Cu matrix.Meanwhile,the chemical-potential difference induced electron transfer from Cu to Ag,and the two factors jointly led to the upshift of Cu d-band and improved the catalytic activity.Consequently,the CuAg electrode exhibited a high turnover frequency(12 times that of pure Cu),a low overpotential at high current density(superior to platinum foil),and high durability(1.57%decay over 180 h).Our work demonstrates that FSP is a powerful method for preparing self-supporting catalysts of immiscible alloys with high catalytic performance.
基金supported by the Sino-Russian Cooperation Research Project of China (No. 2009DFR50170)the National Natural Science Foundation of China (No.51105182)the College Natural Science Foundation of Jiangsu Province (No. 11KJB460004)
文摘A 3-D finite element model is developed to predict the temperature field and thermally induced residual stress and distortion in laser＋GMAW hybrid welding of 6061-T6 aluminum alloy T-joint. And the characteristics of residual stress distribution and deformation are numerically investigated. In the simulation, the heat source model takes into account the effect of joint geometric shape and welding torch slant on the heat flux distribution and a sequentially coupled thermo-mechanical method is used. The calculated results show that higher residual stress is distributed in and surround the weld zone. Its peak value is very close to the yield strength of base metal. Besides, a large deformation appears in the middle and rear part of the weldment.
