A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both sta...A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both statistically stored dislocations （SSDs） and geometrically necessary dislocations （GNDs） are taken as the internal state variables. The strain gradient hardening in micro-bending of single-grained metal foils was predicted by evolution of GNDs. The predicted results were compared with the micro-hardness distribution of the previous micro-bending experiments of CuZn37 a-brass foils with coarse grains and fine grains. Comparison of the simulated dislocation densities distribution of SSDs and GNDs with the experimental results shows that different micro-hardness distribution patterns of the coarse and fine grain foils can be attributed to the corresponding SSDs and GNDs distributions. The present model provides a physical insight into the deformation mechanism and dislocation densities evolution of the micro-bending process.展开更多
Reported are the results of reduction the bending of thin crystalline silicon solar cells after printing and sintering of back electrode by changing the back electrode paste and adjusting the screen printing parameter...Reported are the results of reduction the bending of thin crystalline silicon solar cells after printing and sintering of back electrode by changing the back electrode paste and adjusting the screen printing parameters without effecting the electrical properties of the cell.Theory and experiments showed that the bending of the cell is changed with its thickness of substrate,the thinner cell,the more serious bending.The bending of the cell is decreased with the thickness decrease of the back contact paste.The substrate with the thickness of 190 μm printing with sheet aluminum paste shows a relatively lower bend compared with that of the substrate printing with ordinary aluminum paste,and the minimum bend is 0.55 mm which is reduced by 52%.展开更多
基金Projects(50835002,50821003,50975174,51275297)supported by the National Natural Science Foundation of ChinaProjects(200802480053,20100073110044)supported by the PhD Programs Foundation of Ministry of Education of China
文摘A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both statistically stored dislocations （SSDs） and geometrically necessary dislocations （GNDs） are taken as the internal state variables. The strain gradient hardening in micro-bending of single-grained metal foils was predicted by evolution of GNDs. The predicted results were compared with the micro-hardness distribution of the previous micro-bending experiments of CuZn37 a-brass foils with coarse grains and fine grains. Comparison of the simulated dislocation densities distribution of SSDs and GNDs with the experimental results shows that different micro-hardness distribution patterns of the coarse and fine grain foils can be attributed to the corresponding SSDs and GNDs distributions. The present model provides a physical insight into the deformation mechanism and dislocation densities evolution of the micro-bending process.
基金Yunnan Provincial Natural Science Fundation(2007E197 M)
文摘Reported are the results of reduction the bending of thin crystalline silicon solar cells after printing and sintering of back electrode by changing the back electrode paste and adjusting the screen printing parameters without effecting the electrical properties of the cell.Theory and experiments showed that the bending of the cell is changed with its thickness of substrate,the thinner cell,the more serious bending.The bending of the cell is decreased with the thickness decrease of the back contact paste.The substrate with the thickness of 190 μm printing with sheet aluminum paste shows a relatively lower bend compared with that of the substrate printing with ordinary aluminum paste,and the minimum bend is 0.55 mm which is reduced by 52%.
