Delocalizing strain in a thin metal film on a polymer substrate
Delocalizing strain in a thin metal film on a polymer substrate
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DOI：
10.1016/j.mechmat.2004.02.002
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发表时间：
2005-02-01
影响因子：
3.9
通讯作者：
Suo, Z
中科院分区：
文献类型：
--
作者：
Li, T;Huang, ZY;Suo, Z
在张力下，独立的薄金属膜通常以比其大块对应物更小的应变破裂。通常这种明显的脆性不是由解理引起的，而是由应变局部化引起的，如颈缩。通过体积守恒，颈缩导致局部伸长。该伸长比膜长度小得多，并且几乎不增加总应变。当总应变刚好超过颈缩起始应变时，膜破裂，对于弱硬化膜，颈缩起始应变不超过其弹性极限。现在考虑在急剧硬化的聚合物基底上的弱硬化金属膜。如果金属膜完全结合到聚合物基底上，则基底抑制膜中的大的局部伸长，使得金属膜可以均匀地变形，远远超过λ（N）。然而，如果金属膜从基底上脱粘，则膜变得独立并在比完全结合的膜更小的应变下破裂;聚合物基底保持完整。我们研究了聚合物衬底上的金属薄膜中的应变离域，通过分析初始和大幅度的不均匀变形，以及脱粘辅助颈缩。理论上的考虑需要进一步的实验来阐明金属-聚合物层压板的断裂行为。(C)2004爱思唯尔有限公司保留所有权利。
Under tension, a freestanding thin metal film usually ruptures at a smaller strain than its bulk counterpart. Often this apparent brittleness does not result from cleavage, but from strain localization, such as necking. By volume conservation, necking causes local elongation. This elongation is much smaller than the film length, and adds little to the overall strain. The film ruptures when the overall strain just exceeds the necking initiation strain, epsilon(N), which for a weakly hardening film is not far beyond its elastic limit. Now consider a weakly hardening metal film on a steeply hardening polymer substrate. If the metal film is fully bonded to the polymer substrate, the substrate suppresses large local elongation in the film, so that the metal film may deform uniformly far beyond epsilon(N). If the metal film debonds from the substrate, however, the film becomes freestanding and ruptures at a smaller strain than the fully bonded film; the polymer substrate remains intact. We study strain delocalization in the metal film on the polymer substrate by analyzing incipient and large-amplitude nonuniform deformation, as well as debond-assisted necking. The theoretical considerations call for further experiments to clarify the rupture behavior of the metal-on-polymer laminates. (C) 2004 Elsevier Ltd. All rights reserved.