Li Jianjun, Lu Wenjun, Zhang Siyuan, Raabe Dierk
College of Mechanical and Electrical Engineering, Central South University, Changsha, 410083, Hunan, China.
Department of Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, 40237, Germany.
Sci Rep. 2017 Sep 12;7(1):11371. doi: 10.1038/s41598-017-11001-w.
Nanolayered metallic composites are much stronger than pure nanocrystalline metals due to their high density of hetero-interfaces. However, they are usually mechanically instable due to the deformation incompatibility among the soft and hard constituent layers promoting shear instability. Here we designed a hybrid material with a heterogeneous multi-nanolayer architecture. It consists of alternating 10 nm and 100 nm-thick Cu/Zr bilayers which deform compatibly in both stress and strain by utilizing the layers' intrinsic strength, strain hardening and thickness, an effect referred to as synergetic deformation. Micropillar tests show that the 6.4 GPa-hard 10 nm Cu/Zr bilayers and the 3.3 GPa 100 nm Cu layers deform in a compatible fashion up to 50% strain. Shear instabilities are entirely suppressed. Synergetic strengthening of 768 MPa (83% increase) compared to the rule of mixture is observed, reaching a total strength of 1.69 GPa. We present a model that serves as a design guideline for such synergetically deforming nano-hybrid materials.
由于具有高密度的异质界面，纳米层状金属复合材料比纯纳米晶金属要强得多。然而，由于软硬成分层之间的变形不相容性会促进剪切不稳定性，它们通常在机械性能上不稳定。在此，我们设计了一种具有异质多纳米层结构的混合材料。它由交替排列的10纳米和100纳米厚的铜/锆双层组成，通过利用各层的固有强度、应变硬化和厚度，在应力和应变方面实现了相容变形，这种效应被称为协同变形。微柱测试表明，硬度为6.4吉帕的10纳米铜/锆双层和3.3吉帕的100纳米铜层在高达50%的应变下以相容方式变形。剪切不稳定性被完全抑制。与混合法则相比，观察到协同强化了768兆帕（增加了83%），总强度达到1.69吉帕。我们提出了一个模型，可作为此类协同变形纳米混合材料的设计指南。
