AZ31 Sheet Forming by Clustering Ball Spinning-Analysis of Damage Evolution Using a Modified GTN Model

Abstract

Clustering ball spinning (CBS) forming is a novel approach to manufacturing a complex curved surface. In order to explore the forming limit of magnesium alloy in the CBS forming process, the modified GTN model was incorporated into the FE simulation to analyze the damage evolution. The theoretical analyses are conducted to investigate the deformation mechanism and to explore the stress state in the CBS forming process. The numerical results show that the modified GTN model can predict the result more accurately compared with the standard GTN model, and the damage parameters for GTN model are determined by the experiments. Besides, the forming limit of AZ31 magnesium alloy can be improved by CBS forming method. To explore the reason for the increased forming limit, the microstructure of curved surface was tested by electron backscattered scattering detection (EBSD). The results demonstrate that the deformation of magnesium alloy plate by the CBS method is dominated initially by the extension twinning, and non-basal slip systems are activated with the development of forming process.

Failure behaviors and processing maps with failure domains for hot compression of a powder metallurgy Ni-based superalloy

“…Zhao et al [15] used the GTN damage model to simulate the influence of MC carbides on fracture behaviors of an Inconel 718 sheet during thermally assisted deformation. The GTN model has been also widely applied or extended for modeling the ductile fracture of other metals such as steel [16,17], Al [18][19][20], Mg [21], and under a broad range of stress states [22][23][24]. More about the GTN model and its modifications can be referred to from a recent review by Lee and Basaran [25].…”