小变形下拉伸速度对Al-Ce合金内耗的影响

采用葛氏倒扭摆内耗测试仪研究了含0．013％和0．069％稀土元素Ce的Al—Ce合金，在延伸率(δ）为5％的小变形条件下，拉伸速度对Al—Ce合金晶界内耗的影响．结果表明：与未拉伸变形的样品相比，经拉伸变形试样随拉伸速度的增加，晶界内耗峰向低温发生移动，峰高降低，高温背景内耗升高．Ce含量高的样品，晶界内耗峰的峰高降低更显著．主要机制是拉伸速度增加导致退火后晶粒细化，晶粒尺寸(G．S．)减小，晶界“无序原子群”数量增加．促进稀土元素Ce强烈偏析到晶界处，与Al及Al中的杂质形成沉淀颗粒，造成晶界沉淀内耗峰的结果．

The Effect of the Tensile Rate on the Internal Friction in Al-Ce Alloy under the Small Deformation Condition

By using the tester for internal friction based on the Ke's inverted torsion pendulum, the effect of the tensile rate on the alloy grain boundary internal friction in Al-0.013wt%Ce and Al-0.069wt%Ce alloys is discussed under the deformation ratio of less than 5% condition. The result shows that, compared with the untensile samples, with the tensile rate increasing, the grain boundary internal friction peak in deformed samples shifts to a lower temperature, and meanwhile, the peak height reduces and the high temperature background internal friction gets stronger. In the samples containing more Ce atoms, this tendency becomes more remarkable. The reason might be that the grain gets fine during the annealing treatment when the sample is undergone deformation, which results in the decrease of the grain size and increase of the number of disorder atom group. Therefore, Ce atoms segregate dramatically at grain boundaries and form the precipitated particles with Al atoms or other impurities so that an internal friction is produced.