Hierarchical surface features for improved bonding and fracture toughness of metal-metal and metal-composite bonded joints
Hierarchical surface features for improved bonding and fracture toughness of metal-metal and metal-composite bonded joints
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DOI：
10.1016/j.ijadhadh.2015.12.005
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发表时间：
2016-04-01
影响因子：
3.4
通讯作者：
Feih, Stefanie
中科院分区：
文献类型：
--
作者：
Nguyen, Alex T. T.;Brandt, Milan;Feih, Stefanie
在航空航天和其他工业中，涉及将选择性激光熔化（SLM）钛粘结到钛或复合材料的结构粘合剂接头具有显著的重量和成本节省潜力。然而，所制造的SLM钛的结合潜力在很大程度上是未知的，并且尚未探索或表征使用额外的分层表面特征。在这里，我们证明了SLM的使用，在不同的长度尺度的两个表面特征的层次结构可以提高金属-金属和金属-复合材料粘接接头的断裂韧性。在一个长度尺度（10 - 15 μ m）下，我们通过断裂韧性测试确定SLM表面的固有不规则粗糙度使金属-金属粘合接头（K-Ic = 1.38 kJ/m（2））和混合金属-复合材料共固化接头（K-Ic = 1.20 kJ/m（2））的结合潜力最大化。然后，我们结合这与表面特征在一个更大的长度尺度（200 μ m）。对于金属-复合材料接头，发现使用凹槽表面特征可使裂纹路径偏转，对于向外突出的凹槽，其可使接头的断裂韧性增加高达50%，达到K-Ic = 1.65 kJ/m（2）的值。我们确定了断裂韧性的上升作为一个组合的裂纹路径长度的增加和从纯模式I的混合模式裂纹增长的转变。我们发现，这两个因素的相对贡献大致相等。这项工作表明，SLM制造的钛可以有显着的优势，比传统的钛粘接接头。与传统技术相比，SLM表面可以用于粘合剂粘合，而不需要昂贵且耗时的表面制备，并且设计自由度允许可以显着提高性能的表面特征。(C)2015爱思唯尔有限公司版权所有。
Structural adhesive joints involving Selective Laser Melting (SLM) titanium bonded to titanium or to a composite material have significant potential for weight and cost saving in aerospace and other industries. However, the bonding potential of as-manufactured SLM titanium is largely unknown, and the use of additional hierarchical surface features has not been explored or characterised. Here we demonstrate with the use of SLM that a hierarchy of two surface features at different length scales can improve the fracture toughness of metal-metal and metal-composite bonded joints. At one length scale (10-15 mu m), we established through fracture toughness testing that the intrinsic irregular roughness of the SLM surface maximises the bonding potential for both metal-metal adhesive joints (K-Ic=1.38 kJ/m(2)) and hybrid metal-composite co-cured joints (K-Ic=1.20 kJ/m(2)). We then combined this with surface features at a larger length scale (200 mu m). For metal-composite joints, the use of groove surface features was found to deflect the crack path, which increased the fracture toughness of the joint by up to 50% for outward protruding grooves to a value of K-Ic=1.65 kJ/m(2). We identified the rise in fracture toughness as a combination of an increase in the crack path length and a shift from pure mode I to a mixed-mode crack growth. We found that the relative contributions of these two factors were approximately equal. This work demonstrates that SLM-manufactured titanium can have significant advantages over conventional titanium for bonded joints. In comparison with conventional techniques, SLM surfaces can be used in adhesive bonds without the need for expensive and time-consuming surface preparation, and the design freedom allows for surface features that can significantly improve performance. (C) 2015 Elsevier Ltd. All rights reserved.