描述:
用传统的半连续铸造工艺制备φ90 mm AZ31镁合金圆柱铸锭,利用光学显微镜(OM)和扫描电镜(SEM)观察并分析不同二次冷却水量和抽坯速度对显微组织的影响规律.结果表明:铸锭内存在大量一次及较发达的二次枝晶;随着冷却水量的增加,冷却速度增大,铸锭组织逐渐变得细小均匀;当冷却水量为58 L/min时达到极值,此后组织不再明显变化.拉坯速度的变化对组织影响不大.且受二次冷却水单向导热的影响,试样的纵截面存在粗大的蔷薇状枝晶和尺寸较长的柱状晶.由于结晶器的相对高度较大,铸锭由内到外的组织有增大趋势.
描述:
Some historical oil paintings suffer from damaging by white crystalline inorganic substances precipitated after long years. Main component of the white crystals are inorganic pigments containing heavy metals, it is necessary to confirm morphology and composition of the inorganic crystalline materials taken from various parts of the paintings. Herein we observed morphology and analyzed chemical deposition with EPMA (Electron Probe Micro Analyzer) and measured UV-Vis (ultra violet-visible), fluorescence, and IR (infrared) spectra for several microcrystals taken from ground layer, pigments, and surface of some Japanese oil paintings drawn in the 19th century by the same cultural policy.