To explore the complex thermal-mechanical-chemical behavior in the solid-liquid cast-roll bonding(SLCRB) of Cu/Al cladding strip, numerical simulations were conducted from both macro and micro scales. In macro-scale, ...To explore the complex thermal-mechanical-chemical behavior in the solid-liquid cast-roll bonding(SLCRB) of Cu/Al cladding strip, numerical simulations were conducted from both macro and micro scales. In macro-scale, with birth and death element method, a thermo-mechanical coupled finite element model(FEM) was set up to explore the temperature and contact pressure distribution at the Cu/Al bonding interface in the SLCRB process. Taking these macro-scale simulation results as boundary conditions, we simulated the atom diffusion law of the bonding interface by molecular dynamics(MD) in micro-scale. The results indicate that the temperature in Cu/Al bonding interface deceases from 700 to 320 ℃ from the entrance to the exit of caster, and the peak of contact pressure reaches up to 140 MPa. The interfacial diffusion thickness depends on temperature and rolling reduction, higher temperature results in larger thickness, and the rolling reduction below kiss point leads to significant elongation deformation of cladding strip which yields more newborn interface with fresh metal and make the diffusion layer thinner. The surface roughness of Cu strip was found to be benefit to atoms diffusion in the Cu/Al bonding interface. Meanwhile, combined with the SEM-EDS observation on the microstructure and composition in the bonding interface of the experimental samples acquired from the castrolling bite, it is revealed that the rolling reduction and severe elongation deformation in the solid-solid contact zone below kiss point guarantee the satisfactory metallurgical bonding with thin and smooth diffusion layer. The bonding mechanisms of reactive diffusion, mechanical interlocking and crack bonding are proved to coexist in the SLCRB process.展开更多
Based on twin-roll casting technology and multi-roll groove rolling technology,a Multi-Roll Solid-Liquid Cast-Rolling Bonding(MRSLCRB)process was proposed to fabricate Cu/steel cladding bars,which processes the advant...Based on twin-roll casting technology and multi-roll groove rolling technology,a Multi-Roll Solid-Liquid Cast-Rolling Bonding(MRSLCRB)process was proposed to fabricate Cu/steel cladding bars,which processes the advantages of short flow and high-efficiency.However,it is a typical 3-D thermal-fluid-mechanics coupled problem,and determining cast-rolling force is difficult during the equipment design.Therefore,the geometrical evolution of the cast-rolling area was studied,laying the foundation to establish contact boundary equations and analyze mechanical schematics and metal flow.Then,a 3-D steady-state thermal-fluid coupled simulation model,including casting roll,substrate bar,and cladding metal,was established.The Kissing Point(KP)height,average outlet temperature,and process window were predicted,and simulation results of the three-roll layout indicate that the KP distribution along the circumferential direction can be considered uniform.Hence,the engineering cast-rolling force model was derived based on the differential element method and plane deformation hypothesis.The accuracy was verified by the 3-D finite element model,and the influences of process layouts and technological parameters on the castrolling force were analyzed.Through the indirect multi-field coupled analysis method,the temperature–pressure evolution and reasonable process window can be predicted,which provides a significant basis for guiding equipment design and improving product quality.展开更多
基金Funded by the General Program of National Natural Science Foundation of China(Nos.51474189 and 51674222)the Excellent Youth Foundation of Hebei Scientific Committee,China(No.E2018203446)the Scientific Research Foundation of the Higher Education Institutions of Hebei Province,China(No.QN2015214)
文摘To explore the complex thermal-mechanical-chemical behavior in the solid-liquid cast-roll bonding(SLCRB) of Cu/Al cladding strip, numerical simulations were conducted from both macro and micro scales. In macro-scale, with birth and death element method, a thermo-mechanical coupled finite element model(FEM) was set up to explore the temperature and contact pressure distribution at the Cu/Al bonding interface in the SLCRB process. Taking these macro-scale simulation results as boundary conditions, we simulated the atom diffusion law of the bonding interface by molecular dynamics(MD) in micro-scale. The results indicate that the temperature in Cu/Al bonding interface deceases from 700 to 320 ℃ from the entrance to the exit of caster, and the peak of contact pressure reaches up to 140 MPa. The interfacial diffusion thickness depends on temperature and rolling reduction, higher temperature results in larger thickness, and the rolling reduction below kiss point leads to significant elongation deformation of cladding strip which yields more newborn interface with fresh metal and make the diffusion layer thinner. The surface roughness of Cu strip was found to be benefit to atoms diffusion in the Cu/Al bonding interface. Meanwhile, combined with the SEM-EDS observation on the microstructure and composition in the bonding interface of the experimental samples acquired from the castrolling bite, it is revealed that the rolling reduction and severe elongation deformation in the solid-solid contact zone below kiss point guarantee the satisfactory metallurgical bonding with thin and smooth diffusion layer. The bonding mechanisms of reactive diffusion, mechanical interlocking and crack bonding are proved to coexist in the SLCRB process.
基金This study was co-supported by the National Key Research and Development Program,China(No.2018YFA0707300)the National Natural Science Foundation of China(Nos.51974278 and 52205406)+2 种基金China Post Doctoral Science Foundation(No.2023M732572)the Key Science and Technology Project of Shanxi Province,China(No.20191102009)the Fundamental Research Program of Shanxi Province,China(No.202203021212289).
文摘Based on twin-roll casting technology and multi-roll groove rolling technology,a Multi-Roll Solid-Liquid Cast-Rolling Bonding(MRSLCRB)process was proposed to fabricate Cu/steel cladding bars,which processes the advantages of short flow and high-efficiency.However,it is a typical 3-D thermal-fluid-mechanics coupled problem,and determining cast-rolling force is difficult during the equipment design.Therefore,the geometrical evolution of the cast-rolling area was studied,laying the foundation to establish contact boundary equations and analyze mechanical schematics and metal flow.Then,a 3-D steady-state thermal-fluid coupled simulation model,including casting roll,substrate bar,and cladding metal,was established.The Kissing Point(KP)height,average outlet temperature,and process window were predicted,and simulation results of the three-roll layout indicate that the KP distribution along the circumferential direction can be considered uniform.Hence,the engineering cast-rolling force model was derived based on the differential element method and plane deformation hypothesis.The accuracy was verified by the 3-D finite element model,and the influences of process layouts and technological parameters on the castrolling force were analyzed.Through the indirect multi-field coupled analysis method,the temperature–pressure evolution and reasonable process window can be predicted,which provides a significant basis for guiding equipment design and improving product quality.