TC4-DT钛合金疲劳裂纹扩展性能研究

Study on fatigue crack propagation of TC4-DT titanium alloy

疲劳裂纹扩展性能是衡量材料损伤容限性能的重要指标之一,准确获得材料的疲劳裂纹扩展性能是飞机结构设计所必需的。影响获得疲劳裂纹扩展性能的因素有很多,实验用试样的加工、测试标准的选取、实验机的校核及后期数据的处理方法都会对最终得到的性能数据产生影响。学生通过分组协作的方式完成了TC4-DT钛合金锻件疲劳裂纹扩展实验并获得了描述疲劳裂纹扩展性能的da/dN-ΔK曲线,讨论了不同应力比、不同实验环境和不同取样方向对疲劳裂纹扩展性能的影响。通过协作实验有助于学生全面了解材料疲劳裂纹扩展性能的获取方法,深刻理解疲劳裂纹扩展性能对飞机结构设计的重要性,取得了很好的实验教学效果。

Fatigue crack propagation is one of the important indexes to measure the damage tolerance of materials.Accurate acquisition of material fatigue crack propagation performance is necessary for aircraft structural design.There are many factors that affect the performance of fatigue crack propagation.The processing of the test specimen,the selection of the test standard,the correction of the testing machine and the processing method of the data will have an effect to the final performance.Students completed the fatigue crack propagation experiment of TC4-DT titanium alloy by means of cooperation.The students obtained the da/dN-ΔK curve describing the fatigue crack growth performance.The effects of different stress ratios,different experimental environments and different sampling directions on fatigue crack growth were discussed.Students have mastered the material fatigue crack propagation performance acquisition method through experiment,and understand the importance of fatigue crack propagation performance to aircraft structural design.The experimental course has achieved a good experimental teaching effect.