激光冲击强化对TC11抗外物损伤能力的影响

Effect of Laser Shock Process on Resistance of TC11 to Foreign Object Damage

为实现激光冲击强化技术在航空发动机风扇/发动机叶片上的有效应用,针对强化后钛合金抗外物损伤能力研究不够深入的问题,先后开展TC11钛合金的激光冲击强化试验以及外物损伤试验。首先对TC11钛合金平板试验件进行激光冲击强化试验,分别测试强化与未强化试验件材料硬度和残余应力。测试结果表明激光冲击强化显著提高了试验件0~0.2 mm深度的显微硬度以及0~0.8 mm深度的残余压应力。使用空气炮法对强化与未强化的试验件进行外物损伤试验,测量损伤的宏观尺寸,并观测试验件的金相组织。测试结果表明:激光冲击强化有效地减小损伤凹坑的深度;经过外物冲击后,晶粒发生明显的破碎现象;激光冲击强化能显著提高试验件表面与近表层的残余压应力,且激光冲击强化会细化试验件表面组织,从而提升基体材料的显微硬度,有效减少外物冲击带来的损伤。研究了激光冲击强化对外物损伤宏观的影响规律,并且从损伤的微观特征来解释强化对TC11材料抗外物损伤能力的提升。

In order to realize its effective application in aero-engine fan/compressor blades and study the effect on the ability of resistance to foreign object damage and in view of the problem that the research on the resistance of titanium alloy to foreign object damage is not thorough enough, the laser shock process test and foreign object damage test of TC11 titanium alloy are successively carried out. The TC11 titanium alloy flat plate sample is subjected to laser shock process test, and the hardness and residual stress of the material are tested. The test results show that laser shock process significantly improves the microhardness of the test piece at a depth of 0~0.2 mm and the residual compressive stress at a depth of 0~0.8 mm. The air cannon method is used to conduct a foreign object damage test on the strengened samples and base samples. The macroscopic size of the damage is measured and the metallo-graphic structure of the test samples is observed. The test results show that the laser shock process effectively reduces the depth of the damage pits and the crystal grains are obviously broken. The experimental results show that the residual compressive stress on the surface and near surface of the sample can be significantly improved by laser shock process. And laser shock process can refine the surface structure of the test piece, improving the microhardness of the matrix material, which effectively reduces the damage caused by foreign object damage. The influence law of laser shock process on the macro characteristics of foreign object damage is studied. Furthermore, the enhancement of TC11 resistance to foreign object damage by strengthening is explained from the microscopic characteristics of damage.