变参数激光冲击TC17钛合金疲劳裂纹扩展特性

发布时间：2018-10-30 10:41

【摘要】：研究采用两种不同变能量参数激光冲击TC17钛合金,通过疲劳试验分析变能量参数激光冲击对其疲劳裂纹扩展寿命和扩展速率的影响规律,通过X射线残余应力测试仪分析激光冲击后试件表面残余应力分布状态。结果表明:相比于未强化试件,在高数值残余压应力作用下的强化后试件疲劳寿命分别提高了2.14倍和1.74倍,稳定扩展初期疲劳裂纹扩展速率分别降低了21%和16%;在裂纹稳定扩展前期区域,LP-1试件扩展速率发生明显减小的现象,C'值最大,m值为最小,减为负数;LP-2试件C'值增大,m值减小。残余应力场分布是疲劳裂纹扩展的主要影响因素,两种强化方案对TC17钛合金疲劳裂纹扩展均产生抑制作用,激光能量越大,产生残余压应力值越大,激光冲击对裂纹扩展前期区域的强化作用大于对裂纹扩展中后期区域的强化作用。
[Abstract]:In this paper, two kinds of laser with different energy parameters were used to shock TC17 titanium alloy. The influence of laser shock on fatigue crack growth life and propagation rate was analyzed by fatigue test. The distribution of residual stress on the surface of the specimen after laser shock was analyzed by X-ray residual stress tester. The results show that the fatigue life of the specimens strengthened under high numerical residual compressive stress is increased by 2.14 times and 1.74 times, respectively, and the fatigue crack growth rate at the initial stage of steady growth is reduced by 21% and 16%, respectively. In the early stage of stable crack growth, the growth rate of LP-1 specimen decreases obviously, the C' value is the largest, the m value is the minimum, and the LP-2 specimen C' value increases, and the m value decreases. The distribution of residual stress field is the main influencing factor of fatigue crack growth. Both of the two strengthening schemes can inhibit the fatigue crack growth of TC17 titanium alloy. The higher the laser energy, the greater the residual compressive stress. The effect of laser shock on the early region of crack growth is greater than that on the region of middle and late stage of crack growth.
【作者单位】：空军工程大学等离子体动力学重点实验室;
【基金】：国家自然科学基金项目(No.51505496)资助
【分类号】：TG115;TN249

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