Interfacial Structures Governed Plastic Deformation Behaviors in Metallic Multilayers

doi:10.1007/s40195-016-0377-2

Abstract

Abstract:

In this work, we have investigated the mechanical properties of Cu/Ta, Ag/Cu and Ag/Nb multilayers with different heterogeneous interfaces. The results suggest that when individual layer thickness (h) is larger than 5-10 nm, the hardness/strength of three different multilayer systems has the similar length scale effect with decreasing layer thickness, while when h ≤ 5 nm, the three multilayer systems show remarkably different plastic deformation behaviors. The strength curves exhibit the variation trends of unchanging, softening and increasing corresponding to Cu/Ta, Ag/Cu and Ag/Nb multilayers, respectively. The microstructure analysis shows that three kinds of multilayers have totally different interfacial structures, which lead to the different strengthening or softening mechanisms.

Key words: Metallic, multilayers, Plastic, deformation, Interfacial, structures, Strengthening, mechanism

Ming-Zhen Wei, Zhen-Hua Cao, Xiang-Kang Meng. Interfacial Structures Governed Plastic Deformation Behaviors in Metallic Multilayers[J]. Acta Metallurgica Sinica (English Letters), 2016, 29(2): 199-204.

Figures/Tables 6

Table 1 Comparison of three different multilayer systems

Multilayers	Crystal lattice	Interface misfit (%)^a	Interface type
Cu/Ta	fcc/tet	-	Incoherent
Ag/Cu	fcc/fcc	12	Semi-coherent
Ag/Nb	fcc/bcc	1	Coherent

Fig. 1 Typical load-displacement curves of Cu/Ta, Ag/Cu and Ag/Nb multilayers with h = 5 nm

Fig. 2 a Hardness of Cu/Ta, Ag/Cu and Ag/Nb multilayers plotted as a function of h; b strength plotted as a function of h -1/2

Fig. 3 Bright field cross-sectional TEM a and HRTEM b images of Cu/Ta multilayer with h = 5 nm (the light gray layers indicate the Cu layers, and the dark gray layers indicate the Ta layers; the inset in a is the corresponding SAED pattern)

Fig. 4 Bright field cross-sectional TEM a and HRTEM b images of Ag/Cu multilayer with h = 5 nm (the inset in a is the corresponding SAED pattern)

Fig. 5 Bright field cross-sectional TEM a and HRTEM b images of Ag/Nb multilayer with h = 5 nm (the light gray layers indicate the Nb layers, and the dark gray layers indicate the Ag layers; the inset in a is the corresponding SAED pattern)

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