The Experts below are selected from a list of 33264 Experts worldwide ranked by ideXlab platform
Yucel Birol - One of the best experts on this subject based on the ideXlab platform.
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Reversion Treatment to Improve Bake Hardening Response of a Twin-Roll Cast 6016 Automotive Sheet
Materials Science Forum, 2007Co-Authors: Yucel BirolAbstract:Heat-treatable Al-Mg-Si aluminum alloys for automotive Body Panel applications are shipped and formed in T4 temper while still formable and are subsequently given a bake cycle to increase strength by age hardening while the paint is cured. However, the hardening response during the rather short industrial paint-bake is impaired upon natural ageing after the solution treatment. It is thus essential to counteract the adverse effect of natural ageing on bake hardening. While this is often accomplished by an additional ageing cycle before the paint-bake treatment, reversion treatments ought to be used once substantial natural ageing has first taken place to improve the bake hardening response of a twin-roll cast 6016 sheet. The present work was undertaken to improve the paint bake response of a twin-roll cast 6016 sheet by employing reversion treatments before the paint-bake cycle. Reversion treatments between 200°C and 250°C was effective in improving the bake hardening response of the twin-roll cast 6016 sheet which, when processed without reversion, failed to meet in-service strength requirements with a rather poor bake hardening response of 35 MPa.
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pre aging to improve bake hardening in a twin roll cast al mg si alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Yucel BirolAbstract:Abstract Heat-treatable Al–Mg–Si aluminum alloys are increasingly used for automotive Body Panel applications. They are shipped and formed in T4 temper while still formable and are subsequently given a bake cycle to increase strength by age hardening while the paint is cured. The industrial paint-bake treatment, however, is too short to fully exploit the age hardening potential of these alloys. Hence, the microstructure in the conventional T4 temper must be modified by creating clusters that grow and readily transform into coherent precipitates upon paint baking. The present work was undertaken to improve the paint-bake response of a twin-roll cast 6016 sheet by employing artificial aging between the solution treatment and the paint-bake cycle. Pre-aging in a wide temperature range (60–200 °C) was effective in improving the bake hardening response of the twin-roll cast 6016 sheet which, when processed without any pre-aging, failed to meet in-service strength requirements with a rather poor bake hardening response of 35 MPa.
Guang Yang - One of the best experts on this subject based on the ideXlab platform.
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the natural aging and precipitation hardening behaviour of al mg si cu alloys with different mg si ratios and cu additions
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Lipeng Ding, Robert E Sanders, Zhiqing Zhang, Guang YangAbstract:Abstract The natural aging and artificial aging behaviours of Al-Mg-Si-Cu alloys with different Mg/Si ratios and Cu additions were investigated using Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterisation. Excess Si and Cu additions enhanced the alloy hardening ability during natural (NA) and artificial aging (AA). Alloys with low Cu and high Si contents exhibited higher precipitation hardening than alloys rich in Mg during artificial aging. In contrast, the alloys with high amounts of Cu were less dependent on the Mg/Si ratio during precipitation hardening due to their similar aging kinetics. The main precipitate phases that contributed to the peak-aging hardness were the L, Q′ and β″ phases. In the over-aging conditions, the alloys rich in Mg and Cu had finer and more numerous precipitates than their Si-rich equivalents due to the preferential precipitation of the L phase. The combination of excess Mg and high Cu resulted in an alloy with a relatively low hardness in T4 temper and a relatively higher hardness after the paint baking cycle. Thus, this alloy has good potential for use in auto Body Panel applications.
Dongyol Yang - One of the best experts on this subject based on the ideXlab platform.
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elastic plastic finite element analysis of automotive Body Panel stamping processes using dynamic explicit time integration scheme
Journal of Materials Engineering and Performance, 1999Co-Authors: D W Jung, Dongyol YangAbstract:In this article, the elastic-plastic finite element formulations using dynamic explicit time-integration schemes are proposed for numerical analysis of automotive Body Panel stamping processes. A general formulation of finite element simulation for complex sheet forming processes with arbitrarily shaped tools is briefly introduced. In finite element simulation of automotive Body Panel stamping processes, the robustness and stability of computation are important requirements since the computation time and convergency become major points of consideration besides the solution accuracy due to the complexity of geometry and boundary conditions. For analyses of more complex cases with larger and more refined meshes, the explicit method is more time effective than the implicit method, and it has no convergency problem and has the robust nature of contact and friction algorithms, although the implicit method is widely used because of excellent accuracy and reliability. The elastic-plastic scheme is more reliable and rigorous, while the rigid-plastic scheme requires short computation time. The performance of the dynamic explicit algorithms is investigated by comparing the simulation results of forming of complex-shaped automotive Body parts, such as a fuel tank and a rear hinge, with the experimental results. It has been shown that dynamic explicit schemes provide quite similar results to the experimental results. It is thus shown that the proposed dynamic explicit elastic-plastic finite element method enables an effective computation for complicated automotive Body Panel stamping processes.
Lipeng Ding - One of the best experts on this subject based on the ideXlab platform.
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the natural aging and precipitation hardening behaviour of al mg si cu alloys with different mg si ratios and cu additions
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Lipeng Ding, Robert E Sanders, Zhiqing Zhang, Guang YangAbstract:Abstract The natural aging and artificial aging behaviours of Al-Mg-Si-Cu alloys with different Mg/Si ratios and Cu additions were investigated using Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterisation. Excess Si and Cu additions enhanced the alloy hardening ability during natural (NA) and artificial aging (AA). Alloys with low Cu and high Si contents exhibited higher precipitation hardening than alloys rich in Mg during artificial aging. In contrast, the alloys with high amounts of Cu were less dependent on the Mg/Si ratio during precipitation hardening due to their similar aging kinetics. The main precipitate phases that contributed to the peak-aging hardness were the L, Q′ and β″ phases. In the over-aging conditions, the alloys rich in Mg and Cu had finer and more numerous precipitates than their Si-rich equivalents due to the preferential precipitation of the L phase. The combination of excess Mg and high Cu resulted in an alloy with a relatively low hardness in T4 temper and a relatively higher hardness after the paint baking cycle. Thus, this alloy has good potential for use in auto Body Panel applications.
George Husman - One of the best experts on this subject based on the ideXlab platform.
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thermoplastic sandwich structure design and manufacturing for the Body Panel of mass transit vehicle
Composite Structures, 2007Co-Authors: Haibin Ning, Uday K Vaidya, Gregg M Janowski, George HusmanAbstract:Abstract Weight savings in vehicles enhances fuel efficiency and decreases maintenance costs, especially in mass transit systems. Lightweight composite materials, such as glass fiber reinforced polymers, have been used to replace traditional steel and aluminum components. In this paper, a mass transit bus side Body Panel was designed, analyzed, and manufactured using thermoplastic composite materials. The design featured a sandwich composite with E-glass fiber/polypropylene (glass/PP) face sheets and PP honeycomb core as constituents that provide low weight, high strength and energy absorption benefits. The Panel was designed and analyzed using Pro/Engineer 2001 (Pro/E), Altair ® Hypermesh ® 6.0 (Hypermesh) and ANSYS 7.0 (ANSYS). A single diaphragm forming process was used to manufacture the glass/PP face sheets. This process provides excellent consolidation, which was confirmed by microstructural analysis of the face sheets. The face sheets and core material were adhesively bonded and tested to validate the model. The failure of the Body Panel occurred by adhesive failure when the load reached 11.7 kN. The static loading requirements of the American Public Transportation Association (APTA) for the Body Panel were met. The thermoplastic composite Body Panel exhibited excellent weight saving of more than 55% compared to a conventional bus with aluminum skin and supporting steel bars.