Research And FEM Simulation On Rolling Deformation Of Ag/Cu Composite

AgCu4Ni0.5/Cu composite, which is used for production in Chongqing Chuanyi Metallic Funcional Materials CO., LTD., is applied in experiment on finish rolling with several rolling deformations. After rolling, size and microhardness of composite sample is measured, EBSD experiment on composite is carried out. FEM theoretical analysis and numerical simulation of finish rolling are also carried out. By means of experiments above, effect of finish rolling parameters on micro-texture distribution, misorientation distribution, crystal grain size and distribution, sheet size and microhardness etc. is observed in Ag/Cu composite, research of sheet deformation in rolling process is prepared to provide theory of production and control systematically the process.Detailed contents of this dissertation are illustrated as follows:1. Explicit dynamic Finite Element Equation is analyzed in this dissertation, as well as solving control and focus in Large Deformation FEM problem. Combined with lsdyna970 solver in LS-DYNA, some contents of accurately solving process is discussed and feasible method of solving control is put forward. These effective measures are proved to be favourable in computer operation in the following Chapter 4.2. Based on experiments, finite element simulation analysis on finish rolling process of Ag/Cu composite is carried out, with elstoplastic finite element method and FEM software ANSYS/LS-DYNA. Influence of percent reduction and tension on contact force between sheet and rolls, sheet deformation, state of strain etc. is also studied, and the results indicate:1). Increase of percent reduction has greater effect on extrusion quantity in end section than beginning section.2). Along with increase of percent reduction, diference of plastic strain between Ag layer and Cu layer is bigger in end of sheet than in beginning of sheet. Futthermore, uneven plastic strain becomes more and more severe.3). According to curve of rolling force vs. time, there is a peak in early period, rolling force is stable in most of time history. In the end, a small peak occurs again. The curve presents as concave line.4). Resonable percent reduction is favourable to control of sheet section shape. During reduction below 44%, rolling force is relatively stable and can obtain effect in favour of sheet shape.5). Increase of both forward and backward tension can make transverse flow less, to increase deformation in thickness direction and make more even sheet deformation. 6). Changing forward tension solely can get better effect than changing backward tension solely, while changing both forward tension and backward tension at one time gaves us the best effect.7). If equipment capacity permits, it is recommended that bigger tension should be used in production, to make sheet deform evenly, reduce rolling force, optimize and keep sheet shape.3. Verification between rolling experiment and computer simulation is carried out. In situation of reduction of 20%, 33%, 44%, diference of both total thickness and clad thickness between FEM simulation and rolling experiments is little. Error of total thickness is less than 6.7%. Thickness ratio after rolling is close to that before rolling in all range of reduction, and error between experiments and simulation is within the limits of 4%. Thus, thickness ratio after rolling is more important in controlling sheet thickness and shape, making sure of reasonable thickness ratio, and saving precious metal. Meanwhile, according to Microhardness-Deformation Relationship, the accordance with Stress-Strain Relationship in FEM simulation is concluded.4. Making use of Electron Backscatter Diffraction system, effect of different finish rolling reductions on micro-texture distribution, misorientation distribution, crystal grain size and distribution, sheet size and microhardness etc. is observed in Ag/Cu composite after hot-rolling process.1). Rolling deformation make grain of based layer and clad layer in composite fine. Along with increase of reduction, number and proportion of smallest grain becomes big, while that of biggest grain becomes small.2). Sample prepared by finish rolling in this dissertation has deformation texture with characteristic of so-called Copper-type texture of cold rolling. The texture is strengthening part of C-{112} <111>, S-{123} <634>, B-{110} <112> component. Along with the increase rolling reduction, cold texture components intensified gradually and C-{112} <111> components become dominant.3). In the grain boundary misorientaion distribution of Ag and Cu after rolling, the content of small angle boundary is most, which fits the main principle of small angle boundary in rolled sample.