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利用SEM-EDS、FESEM和XRD研究Ni3Si/Zn固-气扩散偶和Ni3Si/Zn固-液扩散偶中周期型层片组织的形成。结果表明,固-液反应中的扩散通道为Ni3Si/(T+γ)/γ/…T/γ/Ni4Zn12Si3/γ/…Ni4Zn12Si3/γ/Ni4Zn12Si3/δ…/Ni4Zn12Si3/δ/Zn(液);固-气反应中的扩散通道为Ni3Si/θ/(T+γ)/γ/…/T/γ/…T/γ/Zn(气)。随着锌扩散流量的增大,扩散通道向富锌方向移动,Ni3Si基体与其最近邻的周期型层片对之间的距离减小。在周期型层片组织形成的初始阶段,γ相在T相基体中不断形核并长大,为降低表面能,最后变为连续的带状组织。根据实验结果和扩散动力学理论分析,探讨Ni3Si/Zn体系中周期型层片显微组织差异的形成原因和形成机理。
The formation of even periodic plies in Ni3Si / Zn solid-gas diffusion couple and Ni3Si / Zn solid-liquid diffusion couple was studied by SEM-EDS, FESEM and XRD. The results show that the diffusion channel in the solid - liquid reaction is Ni3Si / (T + γ) / γ / ... T / γ / Ni4Zn12Si3 / γ / ... Ni4Zn12Si3 / γ / Ni4Zn12Si3 / δ ... / Ni4Zn12Si3 / δ / Zn The diffusion channels in the solid-gas reaction are Ni3Si / θ / (T + γ) / γ / ... / T / γ / ... T / γ / Zn (gas). With the increase of zinc diffusion flux, the diffusion channels move to the zinc-rich direction, and the distance between the Ni3Si matrix and the nearest neighbor periodic ply decreases. In the initial stage of the periodic lamellar organization, the γ phase continuously nucleates and grows in the T-phase matrix. In order to reduce the surface energy, the γ phase becomes a continuous banded structure. Based on the experimental results and diffusion kinetic theory, the formation mechanism and formation mechanism of the periodic microstructure difference in Ni3Si / Zn system were discussed.