A reconstruction technology of finite element meshes based on reversal engineering was applied to solve mesh penetration and separation in the finite element simulation for the divergent extrusion. The 3D numerical si...A reconstruction technology of finite element meshes based on reversal engineering was applied to solve mesh penetration and separation in the finite element simulation for the divergent extrusion. The 3D numerical simulation of the divergent extrusion process in- cluding the welding stage for complicated hollow sections was conducted. Based on the analysis of flowing behaviors, the flowing velocities of the alloy in portholes and near the welding planes were properly controlled through optimizing the expansion angle as well as porthole ar- eas and positions. After the die structure optimization, defects such as warp, wrist, and the wavelike are eliminated, which improves the sec- tion-forming quality. Meanwhile, the temperature distribution in the cross section is uniform. Especially, the temperature of the C-shape notch with a larger thickness is lower than that of other regions in the cross section, which is beneficial for balancing the alloy flowing velocity.展开更多
7055 aluminum alloy plates with the same size were rolled by two processes： small percentage reduction per pass （PRPP） and large percentage reduction per pass, respectively. Meanwhile, the effect of PRPP on the pre...7055 aluminum alloy plates with the same size were rolled by two processes： small percentage reduction per pass （PRPP） and large percentage reduction per pass, respectively. Meanwhile, the effect of PRPP on the precipitates and corrosion resistance of 7055 aluminum alloy plate was investigated. The mechanisms were analyzed and discussed by optical microscopy （OM）, transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM） and electron back-scattered diffraction （EBSD） technique. Large PRPP can improve the corrosion resistance. For the plate rolled by small PRPP, the main precipitate is guinier-preston （GP） zone and continuous grain boundary precipitates （GBPs）, while, for the plate rolled by large PRPP, the main precipitates are the GP zone and η precipitate, and the GBPs are discontinuous.展开更多
文摘A reconstruction technology of finite element meshes based on reversal engineering was applied to solve mesh penetration and separation in the finite element simulation for the divergent extrusion. The 3D numerical simulation of the divergent extrusion process in- cluding the welding stage for complicated hollow sections was conducted. Based on the analysis of flowing behaviors, the flowing velocities of the alloy in portholes and near the welding planes were properly controlled through optimizing the expansion angle as well as porthole ar- eas and positions. After the die structure optimization, defects such as warp, wrist, and the wavelike are eliminated, which improves the sec- tion-forming quality. Meanwhile, the temperature distribution in the cross section is uniform. Especially, the temperature of the C-shape notch with a larger thickness is lower than that of other regions in the cross section, which is beneficial for balancing the alloy flowing velocity.
基金financially supported by the Higher School Science Foundation of Inner Mongolia (No. NJZZ16082)National Natural Science Foundation of China (Nos. 51764043, 51461017 and 51364027)Science Program for Returned Chinese Scholars supported by Inner Mongolia and the Scientific and Technological Program of Innovation and Guidance of Inner Mongolia
文摘7055 aluminum alloy plates with the same size were rolled by two processes： small percentage reduction per pass （PRPP） and large percentage reduction per pass, respectively. Meanwhile, the effect of PRPP on the precipitates and corrosion resistance of 7055 aluminum alloy plate was investigated. The mechanisms were analyzed and discussed by optical microscopy （OM）, transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM） and electron back-scattered diffraction （EBSD） technique. Large PRPP can improve the corrosion resistance. For the plate rolled by small PRPP, the main precipitate is guinier-preston （GP） zone and continuous grain boundary precipitates （GBPs）, while, for the plate rolled by large PRPP, the main precipitates are the GP zone and η precipitate, and the GBPs are discontinuous.
