中文摘要：

研究了TiCu／Zn扩散偶在390和450℃退火后的扩散层组织，发现其扩散区域中形成了3类周期层片对，且γ＋TiZn3层片对的厚度随温度升高而减小，但与退火时间无关．在TiCu／Zn扩散体系中，反应扩散主要受zn原子向TiCu基体端扩散控制，zn原子扩散至TiCu基体界面附近优先形成TiZn3，而Ti原子穿过γ层和cu原子穿过TiZn3层向富zn端长程扩散均很困难，cu原子仅能通过短程扩散聚集形成γ相并长大．周而复始，扩散通道在γ＋TiZn3两相区中来回振荡形成周期层片对，且其间距与形成的先后顺序无关．温度的升高加快了原子扩散和TiZn3层的形成，使层片对变薄．扩散通道往富zn方向穿过三相区后，在经过τ＋TiZn3和τ＋Ti3Zn22两相区时，同样由于Ti和Cu原子长程扩散困难，形成τ＋TiZn3，和τ＋Ti3Zn22周期层片对．

英文摘要：

ABSTRACT The discovery of the periodic layered structure has been concerned over the past years. However, the exact formation mechanism of the structure is still in dispute for the lack of powerful evidence. The TiCu/Zn diffusion couples annealed at 390 or 450 ℃ were experimentally investigated in the present work. Three kinds of periodic layers exist in the diffusion regions. The thickness of the γ＋TiZn3 layers decreased with the annealing tem- perature but was not affected by the annealing time. All the observed phenomena were well interpreted based on the diffusion thermodynamics, kinetics and diffusion path theory. In the TiCu/Zn diffusion couple, the reaction is mainly controlled by the diffusion of Zn atoms towards the TiCu substrate. TiZn3 forms firstly at the boundary of the TiCu substrate and the diffusion region. And the Ti atoms diffuse through the 7/layer or the Cu atoms through the TiZn3 layer are difficult. Therefore, the γ layer is formed by the short-range diffusion and the concentration of the Cu atoms. The cycle repeats and the diffusion path oscillates in the γ＋TiZn3 two-phase region, which results inthe formation of the periodic layered structure. For this reason, the thickness of the layers is not affected by the for- mation sequence. With the increasing of the annealing temperature, both the diffusion rate of the atoms and the for- mation rate of the TiZn3 layer increases, which lead to form a thinner layer. Moreover, for the long-range diffusion of the Ti and Cu atoms in the reaction region it is also difficult in the Zn-rich side, the diffusion path oscillates in the r＋TiZn3 and z＇＋Ti3Zn22 two-phase regions after crossing the three-phase region. Therefore, another two kinds of periodic layered structures form.