Ti555211合金片层组织裂纹扩展的SEM原位观察

In-situ SEM observations of tensile deformation behavior of in a newnear β titanium alloy—Ti555211 with lamellar structure

摘要:

利用SEM原位拉伸实验，研究了Ti555211合金片层组织的拉伸变形和断裂行为。结果表明：在拉伸载荷作用下，片层组织试样中滑移带优先出现在与加载方向大于45°的片层组织上。在裂纹扩展过程中，合金内滑移带的密度均随着载荷的增加逐渐增加，片层组织试样为沿片层和跨片层交叉断裂。原位拉伸试样断口分析表明，韧性断裂是片层组织试样的主要断裂方式。试样断口存在明显剪切唇和大量断裂韧窝。SEM原位拉伸实验分析方法能够对新型Ti555211近β钛合金的变形和断裂行为进行实时跟踪，该方法的研究结果更加具有科学价值和参考意义。

Abstract:

The tensile deformation and fracture behavior of the Ti555211 alloy were investigated using in-situ SEM technology. Results showed that it was found that slip bands were given priority within the lamellar structure with the tensile loading direction for the Ti555211 alloy with initial lamellar structure. As the crack propagated, the slip bands appeared dense. Moreover, for the alloy with initial lamellar structure, the crack propagated from the corners of the indention both across and along the lamellar directions.The Ti555211 alloy with initial lamellar structure show different fracture morphologies. For the alloy with initial lamellar structure, visible shear lips and a number of dimples were observed in fracture. The deformation and fracture behavior of the near-β titanium alloy of Ti555211 can be tracked by the SEM in-situ tensile test method in real time. The results of this method are more scientific and informative.