Fatigue Crack Growth Behavior in TC4-DT Titanium alloy with Different Lamellar Microstructures

摘要:

主要讨论了TC4-DT钛合金不同片层结构的疲劳裂纹扩展行为。通过不同的热处理工艺获得不同的组织结构参数，例如片层宽度和集束尺寸。结果表明，在保证合金力学性能的条件下，β相区空冷获得的组织具有较好的疲劳性能，主要归因于片层结构中裂纹尖端存在较大的塑性范围区域，并且较宽的α片层和大的集束尺寸有助于提高合金的断裂韧性和疲劳裂纹扩展阻力

Abstract:

This paper focused on the fatigue crack growth behavior of TC4-DT titanium alloy with different lamellar microstructures. Heat treatments were performed in order to prepare different microstructures with α lamella width and colony size. The results show that on the premise to guarantee adequate mechanical properties, the microstructures formed through air cooling from the β-phase field present better ability to resist fatigue crack propagation. This is attributed to the existing of bigger plastic deformation field in crack tip. It is also found that wide α lamellae and coarse α colony are beneficial to improve fracture toughness and resistance to fatigue crack propagation