巨型台阶的透射电镜观察及其可动性探讨

用透射电镜观察了下贝氏体铁素体宽面上三维形态的巨型台阶，发现巨型台阶可在异相前沿堆积而成尺寸更大的巨型台阶。导致巨型台阶堆积的相为另一片下贝氏体铁素体或下贝氏体碳化物。实验观察到下贝氏体碳化物在巨型台阶前沿奥氏体内析出，而并非在下贝氏体铁素体内析出。有关巨型台阶的堆积与下贝氏体碳化物来源的实验结果为下贝氏体铁素体扩散控制台阶长大机制提供了重要的实验证据。

TEM OBSERVATION AND MOBILITY DISCUSSION OF SUPERLEDGES

The three dimensional morphologies of superledges on the broad faces of lower bainitic ferrite plates have been observed under TEM.It was discovered that superledges may pile up in front of secondary phases to form higher superledges. The secondary phases may be another sympathetic nucleated lower bainitic ferrite plate or lower bainitic Carbide. It has also been observed that lower bainitic carbides precipitate in front of the riser of a superledges on the broad face of bainitic ferrite rather than inside bainitic ferrite. The results as to the pile-up of superledges and the source of lower bainitic carbiues have presented more important to support the diffusion-controlled ledge-wise mechanism of lower bainitic carbide