Length scale effect on the thermal stability of nanoscale Cu/Ag multilayers

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 686; pp. 142 - 149
• Main Authors: Ma, Y.J., Wei, M.Z., Sun, C., Cao, Z.H., Meng, X.K.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 16.02.2017; Elsevier BV
• Subjects: Annealing; Atomic structure; Diffusion; Electron microscopy; Grain boundaries; Grain growth; Heterogeneous interface; Interface stability; Metallic multilayers; Multilayers; Scale effect; Thermal stability; Thickness; Transmission electron microscopy; Heterogeneous interface; Metallic multilayers; Grain growth; Thermal stability
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2017.01.048

The annealing induced grain growth (GG) and heterogeneous interface evolution of Cu/Ag multilayers with individual layer thickness (h) varying from 5 to 50nm were investigated by transmission electron microscopy (TEM). The results demonstrate that the thermal stability of Cu/Ag multilayers exhibits strong length scale dependence. For samples with h<20nm, the heterogeneous interfaces completely disappear when the annealing temperature exceeds 200°C. However, the temperature for stable layered structure can reach 300°C as the h≥20nm, where the interfaces remain remarkably intact. The existence of a large number of grain boundaries (GBs) decrease the stability of multilayers, while more heterogeneous interfaces contribute to resisting atomic diffusion, inhibiting GG. The equilibrium is achieved by a competitive process between GBs diffusion and heterogeneous interfaces resistance. Moreover, the formation of annealing twins in multilayer also significantly improve the microstructural stability.