Technische Universität Darmstadt (TUD), KIT-TUD Joint Research Laboratory Nanomaterials, 64287 Darmstadt, Germany ; Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology (INT), 76021 Karlsruhe, Germany.
Beilstein J Nanotechnol. 2013 Sep 24;4:554-66. doi: 10.3762/bjnano.4.64. eCollection 2013.
The microstructure and mechanical properties of nanocrystalline Pd films prepared by magnetron sputtering have been investigated as a function of strain. The films were deposited onto polyimide substrates and tested in tensile mode. In order to follow the deformation processes in the material, several samples were strained to defined straining states, up to a maximum engineering strain of 10%, and prepared for post-mortem analysis. The nanocrystalline structure was investigated by quantitative automated crystal orientation mapping (ACOM) in a transmission electron microscope (TEM), identifying grain growth and twinning/detwinning resulting from dislocation activity as two of the mechanisms contributing to the macroscopic deformation. Depending on the initial twin density, the samples behaved differently. For low initial twin densities, an increasing twin density was found during straining. On the other hand, starting from a higher twin density, the twins were depleted with increasing strain. The findings from ACOM-TEM were confirmed by results from molecular dynamics (MD) simulations and from conventional and in-situ synchrotron X-ray diffraction (CXRD, SXRD) experiments.
采用磁控溅射法制备的纳米晶 Pd 薄膜的微观结构和力学性能作为应变的函数进行了研究。将薄膜沉积在聚酰亚胺基板上，并进行拉伸模式测试。为了跟踪材料中的变形过程，将几个样品应变至定义的应变状态，最大工程应变为 10%，并准备进行事后分析。通过透射电子显微镜（TEM）中的定量自动晶体取向映射（ACOM）研究了纳米晶结构，确定了晶粒长大和孪晶/脱孪晶作为导致宏观变形的两个机制之一。根据初始孪晶密度的不同，样品的表现也不同。对于低初始孪晶密度，发现孪晶密度在应变过程中增加。另一方面，从较高的孪晶密度开始，随着应变的增加，孪晶被耗尽。ACOM-TEM 的结果得到了分子动力学（MD）模拟以及传统和原位同步辐射 X 射线衍射（CXRD、SXRD）实验结果的证实。
