Zr-based bulk metallic glass matrix composites (BMGMCs) with a composition of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4- Be10.0 (at%) were fabricated by an innovative process, i.e., semisolid processing plus Bridgman solidifica...Zr-based bulk metallic glass matrix composites (BMGMCs) with a composition of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4- Be10.0 (at%) were fabricated by an innovative process, i.e., semisolid processing plus Bridgman solidification. Different morphologies, distributions, and volume fractions of the crystalline phases can be achieved by tailoring the withdrawal velocity. The largest fi-acture strain of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4Be10.0 (at%) composites with the withdrawal velocity of 1.0 mm/s was found to be 16.7%. The mechanism of plasticity improvement is mainly attributed to the interpenetrated structure of the crystalline phase, which greatly confines the rapid propagation of shear bands.展开更多
The method of using dielectrophoresis (DEP) to assemble graphene between micro-electrodes has been proven to be simple and efficient. We present an optimization method for the kinetic formula of graphene DEP, and di...The method of using dielectrophoresis (DEP) to assemble graphene between micro-electrodes has been proven to be simple and efficient. We present an optimization method for the kinetic formula of graphene DEP, and discuss the simulation of the graphene assembly process based on the finite element method. The simulated results illustrate that the accelerated motion of graphene is in agreement with the distribution of the electric field squared gradient. We also conduct research on the controllable parameters of the DEP assembly such as the alternating current (AC) frequency, the shape of micro-electrodes, and the ratio of the gap between electrodes to the characteristic/geometric length of graphene (λ). The simulations based on the Clausius-Mossotti factor reveal that both graphene velocity and direction are influenced by the AC frequency. When graphene is close to the electrodes, the shape of micro-electrodes will exert great influence on the velocity of graphene. Also, λ has a great influence on the velocity of graphene. Generally, the velocity of graphene would be greater when λ is in the range of 0.4 0.6. The study is of a theoretical guiding significance in improving the precision and efficiency of the graphene DEP assembly.展开更多
基金financial support of the National Natural Science Foundation of China (Nos. 51101110 and 51105267)the Youth Science Foundation of Shanxi Province, China (Nos. 2012021018-1 and 2012021013-1)the Research Project Supported by Shanxi Scholarship Council of China (Nos. 2012-032 and 2012-030)
文摘Zr-based bulk metallic glass matrix composites (BMGMCs) with a composition of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4- Be10.0 (at%) were fabricated by an innovative process, i.e., semisolid processing plus Bridgman solidification. Different morphologies, distributions, and volume fractions of the crystalline phases can be achieved by tailoring the withdrawal velocity. The largest fi-acture strain of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4Be10.0 (at%) composites with the withdrawal velocity of 1.0 mm/s was found to be 16.7%. The mechanism of plasticity improvement is mainly attributed to the interpenetrated structure of the crystalline phase, which greatly confines the rapid propagation of shear bands.
基金Supported by the Basic Research Project of Shanxi Province under Grant No 2015021092the National Natural Science Foundation of China under Grant Nos 61471255,61474079,61501316,51505324 and 51622507the National High-Technology Research and Development Program of China under Grant No 2015AA042601
文摘The method of using dielectrophoresis (DEP) to assemble graphene between micro-electrodes has been proven to be simple and efficient. We present an optimization method for the kinetic formula of graphene DEP, and discuss the simulation of the graphene assembly process based on the finite element method. The simulated results illustrate that the accelerated motion of graphene is in agreement with the distribution of the electric field squared gradient. We also conduct research on the controllable parameters of the DEP assembly such as the alternating current (AC) frequency, the shape of micro-electrodes, and the ratio of the gap between electrodes to the characteristic/geometric length of graphene (λ). The simulations based on the Clausius-Mossotti factor reveal that both graphene velocity and direction are influenced by the AC frequency. When graphene is close to the electrodes, the shape of micro-electrodes will exert great influence on the velocity of graphene. Also, λ has a great influence on the velocity of graphene. Generally, the velocity of graphene would be greater when λ is in the range of 0.4 0.6. The study is of a theoretical guiding significance in improving the precision and efficiency of the graphene DEP assembly.