钛合金BT9低周疲劳变形结构的研究

Study on Low Cycle Fatigue Deformed Structure for Titanium Alloy BT9

在室温下对钛合金BT-9单轴拉压及多轴非比例载荷的低周疲劳试验后,利用扫描电镜及透射电镜对材料的疲劳变形结构进行观测。结果表明:在单轴加载条件下,断口的形貌为韧窝。在非比例加载条件下,断口的形貌为准解理断裂和解理断裂。随着非比例载荷程度(相位角)的增大,断口的形貌由蜂窝状韧窝向河流花样的解理断裂形貌方向发展。

The low-cycle fatigue tests of Titanium alloy BT9 under uniaxial tension-compression and multiaxial non-proportional low-cycle loading were carried out. The scanning electron microscopy and transmission electron microscopy was used to observe the fatigue deformation structure of materials. The results showed that, the fracture surface morphology of the material takes on the dimples under uniaxial loading conditions. The morphology of fracture takes on cleavage fracture and quasi-cleavage fracture under the non-proportional loading conditions. With the degree of non-proportional load （phase angle） increasing, the morphology of fracture surface change from dimples by the honeycomb-like pattern to the river pattern cleavage fracture.