State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Sci Rep. 2016 Dec 23;6:39522. doi: 10.1038/srep39522.
Pure shear fracture test, as a special mechanical means, had been carried out extensively to obtain the critical information for traditional metallic crystalline materials and rocks, such as the intrinsic deformation behavior and fracture mechanism. However, for bulk metallic glasses (BMGs), the pure shear fracture behaviors have not been investigated systematically due to the lack of a suitable test method. Here, we specially introduce a unique antisymmetrical four-point bend shear test method to realize a uniform pure shear stress field and study the pure shear fracture behaviors of two kinds of BMGs, Zr-based and La-based BMGs. All kinds of fracture behaviors, the pure shear fracture strength, fracture angle and fracture surface morphology, are systematically analyzed and compared with those of the conventional compressive and tensile fracture. Our results indicate that both the Zr-based and La-based BMGs follow the same fracture mechanism under pure shear loading, which is significantly different from the situation of some previous research results. Our results might offer new enlightenment on the intrinsic deformation and fracture mechanism of BMGs and other amorphous materials.
纯剪切断裂试验作为一种特殊的力学手段，已被广泛应用于获取传统金属晶体材料和岩石的关键信息，如本征变形行为和断裂机制。然而，对于大块非晶合金（BMGs），由于缺乏合适的试验方法，其纯剪切断裂行为尚未得到系统研究。在这里，我们特别引入了一种独特的非对称四点弯曲剪切试验方法，以实现均匀的纯剪切应力场，并研究两种 BMGs，Zr 基和 La 基 BMGs 的纯剪切断裂行为。系统地分析和比较了各种断裂行为、纯剪切断裂强度、断裂角和断裂表面形貌，并与常规压缩和拉伸断裂进行了比较。我们的结果表明，Zr 基和 La 基 BMGs 在纯剪切加载下遵循相同的断裂机制，这与一些先前的研究结果明显不同。我们的结果可能为 BMGs 和其他非晶材料的本征变形和断裂机制提供新的启示。
