单晶凝固组织的样品尺寸效应

Effect of Sample Size on Solidified SC Structure

通过对不同直径的单晶样品的凝固实验 ,研究了样品尺寸对单晶凝固组织的影响规律。研究发现 ,随样品尺寸减小 ,单晶凝固组织被细化 ,尤其一次枝晶间距λ1 和枝晶间γ′相尺寸对样品尺寸的依赖性更为明显 ;样品尺寸影响的本质在于比表面积的变化 ,进而对凝固过程温度梯度产生影响 ,最终作用于凝固组织和力学性能 ;一次枝晶间距 λ1和枝晶间 γ′尺寸与样品的比表面积近似呈线性关系 ;样品尺寸变化 。

The effects of sample size on solidified SC structure were studied The results show that, the thinner the sample, the finer the structure, specially for the primary dendrite spacing and the size of γ′phase; the real size effect is the ratio of surface area to volume of the sample (A/V) on the temperature gradient and solidified structure and rupture life; primary dendrite spacing and size of interdendritic γ′ phase is a linear function of A/V ratio;the temperature gradient and the rupture life are changed markedly by the variation of sample size