Papers by Author: A.K. Gupta

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Authors: A.K. Gupta, P.H. Marois, David J. Lloyd
Abstract: AA6111 sheet alloy has been used in automotive panel applications in North America and Europe for several years. This alloy exhibits an excellent combination of strength, formability, ageing response and surface appearance following forming and painting operations. Such a combination of properties is obtained by carefully tailoring the processing route to obtain the desired microstructure of the alloy. In recent years, the ability to predict the phase stability in different alloys has improved significantly, and it is now relatively easy to predict the particles that could form in complex multi component alloys during different processing steps. The accuracy of the predictions is dependent on whether or not the free energy expressions used in the calculations are correct. In this study, the AA6111 alloy was subjected to various annealing treatments that are reflective of different phase fields computed by the Thermo-Calc software. The particles were extracted using the phenol extraction technique and were identified using energy dispersive analysis. The interrelation of the particle analyses with the computed phase stability in AA6111 is presented.
Authors: A.K. Gupta, J.B. Bookbinder, H.S. Sang, David J. Lloyd
Authors: A.K. Gupta, P.H. Marois, David J. Lloyd
Authors: Hai Ou Jin, A.K. Gupta
Abstract: The through-thickness textures of different variants of AA6111 T4 sheets were investigated by using X-ray pole figure technique, scanning electron microscopy (SEM), and electron back scattering diffraction (EBSD) technique in SEM. The roping behaviors of the sheets were determined and corelated to the through-thickness texture inhomogeneity. It has been demonstrated that (i) roping is due to through-thickness texture inhomogeneity, (ii) roping occurs in AA6111 when the cube and Goss texture components segregate along the rolling direction (RD) and alternate in the transverse direction (TD), (iii) the texture alignment from sheet surface to 1/5 thickness is most critical to roping behavior, while the effect of texture in the sheet centre is masked by the surface layer, and (iv) the texture alignment can be attributed to the stability of cube and Goss in rolling, and the nucleation and grain growth advantage of cube and Goss during heat treatments.
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