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2758 |
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Tuesday, September 27, 2011, Saal B2.2 12:15 PM Modeling & Simulation 1 |
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A method for residual stress estimation of AZ31 under cold spray coating |
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Ramin Ghelichi* / Politecnico di Milano, Italy Mario Guagliano / Politecnico di Milano, Italy Hamid Jahed/ Waterloo University, Canada Julio Villafuerte/ CenterLine Co,, Canada |
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Magnesium alloys, which are the lightest commercial structural alloys with superior specific strength and stiffness, have become of great interest to the automotive industry in view of their potential to reduce weight and reduce fuel consumption and emissions. One of the most short comes of magnesium is its poor corrosion resistance. Admittedly, surface treatment has become an effective method to improve corrosion resistance of magnesium alloys. Low pressure cold spraying, a novel solid state spraying process, has been used to locally deposit aluminum on AZ31 in order to enhance general and galvanic corrosion of magnesium. Cold spraying induces superficial compressive stresses which may positively affect the fatigue life of the underlying structure. This study is aimed at numerical estimation of the residual stress profile due to cold spray coating using FEM. The impact of particles on the substrate is modeled in Abaqus explicit. The challenge of AZ31 simulations is the intrinsic yield asymmetry and anisotropy which results different behavior of the material along different direction both in tension and compression. On the other hand, there is no material model capable of considering the yield asymmetry and anisotropy experienced by AZ31. This paper studies the effect of anisotropy of the AZ31 on residual stress. The results are compared with experimental X-Ray diffraction measurements of the residual stress on the specimens. This study will suggest the possibility of using an isotropic model in one of the direction of AZ31 in order to estimate the profile of residual stress. |