Ti555211合金双态组织拉伸行为的SEM原位观察

In-situ SEM observations of tensile deformation behavior ofTi555211 alloy with Dual structure

摘要:

利用SEM原位拉伸实验，研究了Ti555211合金具有初始双态组织的拉伸变形和断裂行为。结果表明：在拉伸载荷作用下，双态组织试样中滑移带优先出现在初生α相内（与拉伸轴呈45°），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，双态组织试样的断裂方式为微孔聚集型断裂。原位拉伸试样断口分析表明，韧性断裂是双态组织试样的主要断裂方式，双态组织试样断口没有明显剪切唇，存在小范围的剪切滑移造成的平坦面。SEM原位拉伸实验分析方法能够对该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重大的理论价值和工程意义。

Abstract:

The tensile deformation and fracture behavior of the Ti555211 alloy with dual structure were investigated using in-situ SEM technology. Results showed that It was found that slip bands were given priority within the primary α phase along with angle of 45o with the tensile loading direction for the Ti555211 alloy with initial dual structure. As the crack propagated, the slip bands appeared dense. Moreover, the crack growth was dominant by interconnected microcavities for the alloy with initial dual structure. The Ti555211 alloy with initial dual structure and lamellar structure show different fracture morphologies. For the alloy with initial dual structure, there displayed a small flat surface causing by shear slip, but no obvious shear lip showed 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 research results of this method have great theoretical value and engineering significance.