摘要
采用典型的透明模型合金 ,即丁二腈 1.5at%水杨酸苯酯 (SCN 1.5at%Salol)合金 ,对界面前沿溶质扩散边界层和界面稳定性进行了实时观测 ,并结合丁二腈 1.1wt%乙醇 (SCN 1 1wt%Eth)、丁二腈 0 4 3wt%氧杂萘邻酮 15 2(SCN 0 4 3wt%C15 2 )的实验结果 ,对纯扩散和存在对流情况下的定向凝固界面形态稳定性进行了系统的分析 .发现以往所进行的界面稳定性分析能够准确描述实验中所观测到的界面失稳的时间相关特性 ,并发现界面失稳演化存在两个时间结点 ,即界面失稳孕育时间和平胞转变孕育时间 ,所获得的时间相关解能够准确预测实验中观测到的平胞转变孕育时间 ,而对流效应则明显缩短了界面失稳和平胞转变的孕育时间 .实验中获得的单位扰动振幅发展速率比稳态理论预言值小了将近一个数量级 。
In situ observation on the interface instability and the solute transport boundary layer in front of the solid/liquid interface is carried out during the directional solidification of SCN-1.5at%Salol. Based on this, and in combination with the experimental results of SCN-1.1 wt%Eth, SCN-0.43wt%C152 alloys, the morphological instability of a solidifying planar interface is systematically investigated during directional solidification with and without the convection. It is found that the interface stability analysis in our previous paper describes correctly the time-dependent evolution of interface instability. Both the incubation time t i for instability and the incubation time t b for breakdown of the planar interface can be determined from the time-dependent instability solution, and the convection obviously shortens the incubation time t i for instability and the incubation time t b for breakdown of the planar interface. The steady-state instability solution overestimates the unit amplitude developing rate by an order of magnitude, as compared to the experimental value, while the time-dependent solution underestimates the experimental result.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第11期3978-3983,共6页
Acta Physica Sinica
基金
国家高技术研究发展计划 (批准号 :2 0 0 1AA3 3 70 2 0 )
国家自然科学基金 (批准号 :5 0 2 0 10 12和 5 0 0 710 48)资助的课题~~
