Papers by Keyword: AlCuMg Alloy

Abstract: In the work, numerical calculations of extrusion process of 2024 alloy through porthole dies were performed. The DEFORM 3D program based on Finite Element Method was used. The way of metal flow, distributions of stresses as well as temperature level within the welding chamber were predicted for different geometry of porthole die. Particularly, different height, width, and shape of the welding chamber were adopted in calculations. The calculations allowed predicting both hydrostatic pressure and temperature levels as well their distributions in the welding region providing the best welding conditions for the alloy tested.

Abstract: According to the characteristic of appearing cavitation in the metals during superplastic deformation, the influence of strain rate on cavity evolvement, the influence of cavity on superplastic deformation capability, and the formation, development process of cavity were investigated for Al-Cu-Mg alloy (i.e. coarse–grained LY12). The results show that: ①The pore nucleation occurs not only at triangle grain boundaries, but also along nearby the second phase particles, and even within grains. The cavities at the triangle grain boundaries are present in V-shape, others near the second phase particles and within grains are present in O-shape. These cavities may result from disharmony slippage of grain boundaries. ②The tendency of cavity development decreases with increasing of strain-rate. In lower strain-rate condition, though Al-Cu-Mg alloy has better superplasticity, many big cavities in the specimen may reduce the room temperature properties of the alloy. In higher strain-rate condition, Al-Cu-Mg alloy has certain superplasticity and room temperature properties as well as few cavities forming. By analyzing, viscous layer on grain boundaries is very thin and grain sizes can be refined during their extruding and rotating each other in higher strain-rate superplastic deformation condition. ③Growth and coalescence of cavity are the main reason of the superplastic fracture of Al-Cu-Mg alloy. And small and a certain amount of cavities with dispersion and independence state are very useful to crystal boundary slippage.