高分解能放射光ナノトモグラフィに基づいたイメージベースFEシミュレーションによるAl-Si 鋳造合金における共晶Si 相の応力集中の検討

抄録

  Image-based finite element (FE) simulation, based on images of a model built with 3D images obtained by synchrotron radiation nano-tomography, was performed to investigate the point of preferential damage on Si particles in the early stage of tensile deformation in Al-10%Si casting alloys. By reproducing stress concentration on Si particles with the FE simulation, the effects of particle parameters such as (1) particle size, (2) particle orientation to loading direction, and (3) particle shape on damage were evaluated. Nano-tomography observation suggested that the parameters influence damage. The increasing rate of maximum hydrostatic stress differed depending on the Si particle size. Larger particles showed rapid increment in stress, suggesting that preferential damage may occur in large particles at an early stage of tensile deformation. In the study on the influence of particle orientation, particles whose longitudinal direction are more or less parallel to the tensile direction tend to also show rapid increment in stress. However, the most rapid development of the maximum hydrostatic stress was observed in particles possessing small Gaussian curvature which corresponds to severe necking. Comparisons of particles having specific parameters with damaging behavior revealed that the most influential parameter of particles on stress concentration was particle shape possessing necking.