Papers by Keyword: Reaction Stress

Abstract: Many efforts have been made to simulate the rolling texture evolution in polycrystalline Al for which strain and stress equilibrium of grains need to be considered. The conventional Taylor theory and its modifications, such as current VPSC, ALAMEL, GIA, fail to solve the problem of stress incompatibility between grains and their surrounding matrix properly. A reaction stress model is suggested for rolling deformation, which accounts both for stress and strain equilibrium and predicts similar textures as those by the Taylor theory. The corresponding detailed modification could reproduced the real rolling texture formation if the industrial rolling stress condition is included.

Abstract: Today high-strength structural steels (yield strength ≥ 960 MPa) are increasingly applied. Therefore, weldments have to achieve equal strength. Yet, high residual stresses in those welds diminish the components safety. Especially high restraint intensities can lead to crack-critical stress-levels. A special 2-MN-test facility allowed online-measurements of global reaction forces under defined restraint conditions during welding and cooling of multilayer-component MAG-welds. Local residual stresses were measured via X-ray diffraction before and after relief of the restraint. Local and global stresses were highly affected by heat control.

Abstract: A reaction stress model is introduced in this paper and its applications for the crystallographic texture simulation are also discussed with the comparison to the classic Taylor type model and the self consistent model. This model took the external deformation stress tensor as an initial point, and the activation process of slip systems as well as the orientation evolutions was simulated step by step. Certain relaxation of reaction stress were introduced during tensile or drawing deformation, which predicts the tensile direction distribution along the orientation line between <111> and <100> in the inverse pole figure besides the <111> and <100> fiber texture. The simulation agrees with the common experimental observations. The model supplies a simple way to follow the deformation process in the main part of polycrystals, in which the effect of grain orientation and its interaction with the surrounding matrix are considered.