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The Natural Aging Modeling of 2024 AL alloy after Multi-directional Forging

Nouri, Sasan | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49347 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Kazeminezhad, Mohsen
  7. Abstract:
  8. Metallurgical phenomena modeling help the researchers to understand the influence and contribution of different factors on the alloys properties. One of the most interesting phenomenon is the aging process occuring in age-hardenable alloys like 2xxx aluminium series. A factor which has high impact on aging and there are not proper models for evaluating that, is the contribution of plastic deformation. This factor has contribution not only on the dynamic precipitation (during deformation) but also on the natural aging after plastic deformation. So in this research a model containing the role of plastic deformation on dynamic precipitation and the contribution of dynamic precipitation on total strength is developed for material behaviour during forming processes. The model outputs (flow stress vs. strain) imported to the finite element in order to model the multi-directional forging in 2024 Al alloy. Another equation is also developed, in order to model the strength evolution during natural aging process after plastic deformation. This model also considers the role of pre-deformation on the aging process. In each step, experimental tests are done for evaluating the models predictions. The results show that 2024 alloy strength is increased by imposing more strain in multi-directional forging process. The rate of hardening is decreased with increasing the number of imposed passes. An increase about 100% in yield strength is arised by imposing 2 passes of multi-directional forging. Natural aging also increases the alloy yield strength about 20% in non-deformed samples while this value is less than 5% in deformed ones. The results also show that the yield strength in deformed samples is always higher than that of non-deformed samples, due to the high influence of strain-hardening and dynamic precipitation during plastic deformation
  9. Keywords:
  10. Finite Element Modeling ; Natural Aging ; Modeling ; Aluminum Alloy 2024 ; Multidirectional Forging

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