The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was explored.The non-equilibrium solidification structure of the under cooled alloy ...The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was explored.The non-equilibrium solidification structure of the under cooled alloy samples were analyzed.It is found that the rapidly solidified alloy has undergone twice grain refinement during the undercooling process.Characterization and significance of the maximum undercooling refinement structure of Cu60Ni35Co5 at T=253 K were analyzed.High-density defects were observed,such as dislocations,stacking faults networks,and twinning structures.The standard FCC diffraction pattern represents that it is still a single-phase structure.Based on the metallographic diagram,EBSD and TEM data analysis,it is illustrated that the occurrence of grain refinement under high undercooling is due to stress induced recrystallization.In addition,the laser cladding technology is used to coat Co-based alloy(Stellite12) coating on 304 stainless steel substrate;the microstructure of the coating cross-section was analyzed.It was found that the microstructure of the cross-section is presented as columnar crystals,planar crystals,and disordered growth direction,so that the coating has better hardness and wear resistance.By electrochemical corrosion of the substrate and coating,it can be seen that the Co and Cr elements present in the coating are more likely to form a dense passivation film,which improved the corrosion resistance of the coating.展开更多
By using semisolid joining technique, the bonding of stainless steel and semisolid aluminum alloy is successfully realized. The relationships between interfacial shear strength and solid fraction of aluminum alloy, bo...By using semisolid joining technique, the bonding of stainless steel and semisolid aluminum alloy is successfully realized. The relationships between interfacial shear strength and solid fraction of aluminum alloy, bonding pressure and time of keeping pressure were studied by the method of orthogonal experiment. The interfacial structure and the fracture structure of the bonding plate are studied by means of optical microscope （OM） and scanning electron microscope （SEM）. The results show that there is the best solid fraction between the solid phase line and the liquid phase line of the semisolid aluminum alloy, with the increase of bonding pressure and pressure time, the interfacial shear strength increases rapidly, and then with further increase of bonding pressure and pressure time, the shear strength rises little. Along the interface, solid phase and liquid phase bond with stainless steel by turns because of the different diffusion ability. So, a new type of non-equilibrium diffusion interfacial structure is constructed at the interface of stainless steel and aluminum alloy, compound mechanism of plastic and brittle fracture interface was formed at the shear fracture interface.展开更多
Non-equilibrium problem is discussed in social economics system in this paper. It includes dissipative structure, fluctuation and complication etc.. Two equations are given, which are applied to describle fluctuation ...Non-equilibrium problem is discussed in social economics system in this paper. It includes dissipative structure, fluctuation and complication etc.. Two equations are given, which are applied to describle fluctuation action in social economics system.展开更多
Irreversible drift-diffusion processes are very common in biochemical reactions.They have a non-equilibrium stationary state(invariant measure)which does not satisfy detailed balance.For the corresponding Fokker-Planc...Irreversible drift-diffusion processes are very common in biochemical reactions.They have a non-equilibrium stationary state(invariant measure)which does not satisfy detailed balance.For the corresponding Fokker-Planck equation on a closed manifold,using Voronoi tessellation,we propose two upwind finite volume schemes with or without the information of the invariant measure.Both schemes possess stochastic Q-matrix structures and can be decomposed as a gradient flow part and a Hamiltonian flow part,enabling us to prove unconditional stability,ergodicity and error estimates.Based on the two upwind schemes,several numerical examples–including sampling accelerated by a mixture flow,image transformations and simulations for stochastic model of chaotic system–are conducted.These two structurepreserving schemes also give a natural random walk approximation for a generic irreversible drift-diffusion process on a manifold.This makes them suitable for adapting to manifold-related computations that arise from high-dimensional molecular dynamics simulations.展开更多
基金Funded by the Basic Research Projects in Shanxi Province(No.202103021224183)。
文摘The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was explored.The non-equilibrium solidification structure of the under cooled alloy samples were analyzed.It is found that the rapidly solidified alloy has undergone twice grain refinement during the undercooling process.Characterization and significance of the maximum undercooling refinement structure of Cu60Ni35Co5 at T=253 K were analyzed.High-density defects were observed,such as dislocations,stacking faults networks,and twinning structures.The standard FCC diffraction pattern represents that it is still a single-phase structure.Based on the metallographic diagram,EBSD and TEM data analysis,it is illustrated that the occurrence of grain refinement under high undercooling is due to stress induced recrystallization.In addition,the laser cladding technology is used to coat Co-based alloy(Stellite12) coating on 304 stainless steel substrate;the microstructure of the coating cross-section was analyzed.It was found that the microstructure of the cross-section is presented as columnar crystals,planar crystals,and disordered growth direction,so that the coating has better hardness and wear resistance.By electrochemical corrosion of the substrate and coating,it can be seen that the Co and Cr elements present in the coating are more likely to form a dense passivation film,which improved the corrosion resistance of the coating.
文摘By using semisolid joining technique, the bonding of stainless steel and semisolid aluminum alloy is successfully realized. The relationships between interfacial shear strength and solid fraction of aluminum alloy, bonding pressure and time of keeping pressure were studied by the method of orthogonal experiment. The interfacial structure and the fracture structure of the bonding plate are studied by means of optical microscope （OM） and scanning electron microscope （SEM）. The results show that there is the best solid fraction between the solid phase line and the liquid phase line of the semisolid aluminum alloy, with the increase of bonding pressure and pressure time, the interfacial shear strength increases rapidly, and then with further increase of bonding pressure and pressure time, the shear strength rises little. Along the interface, solid phase and liquid phase bond with stainless steel by turns because of the different diffusion ability. So, a new type of non-equilibrium diffusion interfacial structure is constructed at the interface of stainless steel and aluminum alloy, compound mechanism of plastic and brittle fracture interface was formed at the shear fracture interface.
基金This work is supported by the National Natural Science Foundation of China.
文摘Non-equilibrium problem is discussed in social economics system in this paper. It includes dissipative structure, fluctuation and complication etc.. Two equations are given, which are applied to describle fluctuation action in social economics system.
基金Jian-Guo Liu was supported in part by NSF under awards DMS-2106988by NSF RTG grant DMS-2038056Yuan Gao was supported by NSF under awards DMS-2204288.
文摘Irreversible drift-diffusion processes are very common in biochemical reactions.They have a non-equilibrium stationary state(invariant measure)which does not satisfy detailed balance.For the corresponding Fokker-Planck equation on a closed manifold,using Voronoi tessellation,we propose two upwind finite volume schemes with or without the information of the invariant measure.Both schemes possess stochastic Q-matrix structures and can be decomposed as a gradient flow part and a Hamiltonian flow part,enabling us to prove unconditional stability,ergodicity and error estimates.Based on the two upwind schemes,several numerical examples–including sampling accelerated by a mixture flow,image transformations and simulations for stochastic model of chaotic system–are conducted.These two structurepreserving schemes also give a natural random walk approximation for a generic irreversible drift-diffusion process on a manifold.This makes them suitable for adapting to manifold-related computations that arise from high-dimensional molecular dynamics simulations.
