| 초록 |
Magnesium and its alloys have received much attention in automotive industry due to lightweight property, high strength-to-weight ratio, high specific endurance limit, and good welding capabilities. However, high tension-compression yield asymmetry and strong plastic anisotropy, arising from the limited number of slip systems in the hexagonal close-packed magnesium alloys, hinder a large potential application of magnesium alloys. In this study, in-situ neutron diffraction and elastic-viscoplastic self-consistent (EVPSC) modeling have been used to investigate deformation mechanisms of the loading-unloading process under uniaxial tension and compression in a solid-solution-strengthened extruded Mg-1wt.%Zn alloy. The initial texture is such that the {0002} basal planes in most grains are tilted around 20-30° from the extrusion axis, indicating that basal slip should be easily activated in a majority of grains under tension and compression. Lattice strain and diffraction peak intensity variations are systematically measured during the mechanical testing in order to investigate the micromechanical responses in the bulk polycrystalline sample. The EVPSC model predicts the macroscopic stress-strain responses, lattice strain evolution, and the activities of deformation modes during the course of test. The effects of initial texture and load direction on the activation of deformation modes of magnesium alloys are discussed. |
