The microstructure and mechanical properties of Mg–6Zn–1Y and Mg–6Zn–3Y（wt%） alloys under different cooling rates were investigated. The results show that the second dendrite arm spacing（SDAS） of Mg–6Zn–1Y a...The microstructure and mechanical properties of Mg–6Zn–1Y and Mg–6Zn–3Y（wt%） alloys under different cooling rates were investigated. The results show that the second dendrite arm spacing（SDAS） of Mg–6Zn–1Y and Mg–6Zn–3Y is reduced by 32 and 30% with increasing cooling rates（Rc） from 10.2 to 23 K/s, which can be predicted using a empirical model of SDAS=68 R 0：45：45cand SDAS=73 R 0c, respectively. The compressive strength of both alloys increases with increasing the cooling rate, which is attributed to the increase of volume fraction（Vf） of secondary phases under high cooling rate. The interaction of the cooling rate and component with SDAS has been theoretically analyzed using interdependence theory.展开更多
A visco-plastic rate-dependent homogenization theory for particle-reinforced composites was derived and the equivalent elastic constants and the equivalent visco-plastic parameters of these composites were obtained. A...A visco-plastic rate-dependent homogenization theory for particle-reinforced composites was derived and the equivalent elastic constants and the equivalent visco-plastic parameters of these composites were obtained. A framework of homogenization the- ory for particle-reinforced W-Ni-Fe composites, a kind of tungsten alloy, was established. Based on the homogenization theory and a fixed-point iteration method, a unit cell model with typical microstructnres of the composite was established by using dynamic analysis program. The effects of tungsten content, tungsten particle shape and particle size and interface strength on the mechanical properties and the crack propagation of the W-Ni-Fe composite are analyzed under quasi-static and dynamic loadings. The stress-strain curves of the composite are given and the relation between the macro-mechanical characteristics and the microstructure parameters is explored, which provides an important theoretical basis for the optimization of the W-Ni-Fe composites.展开更多
基金financially supported by the National Natural Science Foundation of China (NO. 51464034)the Cooperation and Exchanges of Nanchang City (2012DWHZXCL@JDYTH-001)+5 种基金the Educational Commission of Jiangxi Province (No. GJJ13069)the Innovation Fund Designated for Graduate Students of Jiangxi Province (No. YC2013-S027)the Hong Kong Scholars Program (No. XJ2012025)the China Post-doctoral Science Foundation funded project (No. 2012T50594, 2014M551866)the Jiangxi Post-doctoral Science Foundation (No. 2014KY11)Doctoral Fund of Ministry of Education of China (No. 20113601110008)
文摘The microstructure and mechanical properties of Mg–6Zn–1Y and Mg–6Zn–3Y（wt%） alloys under different cooling rates were investigated. The results show that the second dendrite arm spacing（SDAS） of Mg–6Zn–1Y and Mg–6Zn–3Y is reduced by 32 and 30% with increasing cooling rates（Rc） from 10.2 to 23 K/s, which can be predicted using a empirical model of SDAS=68 R 0：45：45cand SDAS=73 R 0c, respectively. The compressive strength of both alloys increases with increasing the cooling rate, which is attributed to the increase of volume fraction（Vf） of secondary phases under high cooling rate. The interaction of the cooling rate and component with SDAS has been theoretically analyzed using interdependence theory.
基金supported by the National Natural Science Foundation of China (Grant No. 11032002 and 91016013)the program for New Century Excellent Talents in University+1 种基金National Basic Research Program of China (Grant No. 2010CB832706)the project of State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology)(Grant No. ZDKT10-03a)
文摘A visco-plastic rate-dependent homogenization theory for particle-reinforced composites was derived and the equivalent elastic constants and the equivalent visco-plastic parameters of these composites were obtained. A framework of homogenization the- ory for particle-reinforced W-Ni-Fe composites, a kind of tungsten alloy, was established. Based on the homogenization theory and a fixed-point iteration method, a unit cell model with typical microstructnres of the composite was established by using dynamic analysis program. The effects of tungsten content, tungsten particle shape and particle size and interface strength on the mechanical properties and the crack propagation of the W-Ni-Fe composite are analyzed under quasi-static and dynamic loadings. The stress-strain curves of the composite are given and the relation between the macro-mechanical characteristics and the microstructure parameters is explored, which provides an important theoretical basis for the optimization of the W-Ni-Fe composites.
