Study on Morphological Stability of Interphase Boundary Formed by Diffusional Reaction

不同相界面形貌的控制是复合材料生产的关键技术之一。本工作从实验和热力学的角度对Ti-X、Fe-C基和Ni-Al基体系中的相界面进行了研究。(1)Ti-X体系中的α/β界面：在Ti-X合金的rge α/β扩散偶中，Fe、Co和Ni形成非平面界面。这一结果可能是由于这些元素在α固溶体中的高速扩散所致。 (2)Fe-C-X系中的α/γ界面：Fe-C-X(X：Ti、V、Nb、Ta、Cr、Mo、W、Co和Cr)合金中渗碳形成的α/γ界面是稳定的，而P、Al、Sb、Ni、Mn、Si和Ge则观察到非平面界面。这些结果可以用局部平衡的概念来定量解释。 (3)Ni-Al基扩散对β相的赝界面：在Ni-Al基扩散对β相的单相区域，在浓度分布中观察到有明显浓度下降的界面。这是由于 B2 结构中的扩散系数的异常变化是由于其成分相关的缺陷结构引起的。

The control of morphology of the interface between different phases is one of the key technology in producting composite materials. In the present work, the phase interfaces in Ti-X, Fe-C base and Ni-Al base systems have been studied from the viewpoints of both the experimental and thermodynamics.(1)alpha/beta interface in Ti-X system : In rge alpha/beta diffusion couples of Ti-X alloys, non planar interfaces were formed for Fe, Co and Ni. This result might due to high speed diffusion of these elements in alpha solid solution.(2)alpha/gamma interface in Fe-C-X system : The alpha/gamma interfaces formed by carburization in Fe-C-X (X : Ti, V, Nb, Ta, Cr, Mo, W, Co and Cr) alloys were stable, while non planar interfaces were observed for P, Al, Sb, Ni, Mn, Si and Ge. These results could be explained quantitatively by the concept of the local equilibrium.(3)Pseudo-interface in beta phase of Ni-Al base diffusion couples : In a single phase region of beta phase in the Ni-Al base couples, an interface which has a clear concentration drop was observed in the concentration profile. This is due to the anomalous variations in diffusion coeffecients in B2 structure arising from its composition dependent defect structure.