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采用电子束悬浮区熔定向凝固技术制备了Ni-Ni3Si共晶自生复合材料,在稳态晶体生长区,采用零功率法获取了不同凝固速率的固-液界面。研究表明,随凝固速率的增大,固-液界面的形态发生了明显的变化。在凝固速率较低时,固-液界面基本保持平界面,形成的是规则的层片状共晶组织。随凝固速率的增大,成分过冷增大,平界面失稳,凝固组织的规则性也降低。此外,根据M-S界面稳定性判据,计算了不同凝固速率不同干扰波长对固-液界面稳定性的影响,理论计算与实验结果基本吻合。
Ni-Ni3Si eutectic composites were prepared by melt-solidification technique in electron beam suspension zone. The solid-liquid interface with different solidification rates was obtained by zero-power method in steady-state crystal growth region. The results show that with the increase of the solidification rate, the morphology of the solid-liquid interface changes obviously. When the solidification rate is low, the solid-liquid interface basically maintains a flat interface and forms a regular lamellar eutectic structure. With the increase of the solidification rate, the composition becomes too cold and increases, the flat interface becomes unstable and the regularity of the solidified structure also decreases. In addition, according to the stability criterion of M-S interface, the influences of different interference wavelengths with different solidification rates on the stability of the solid-liquid interface are calculated. The theoretical calculation is in good agreement with the experimental results.