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脉冲激光离散划痕过程中,激光冲击波动态加载及界面破坏在瞬间完成。其所包含的脱粘、裂纹扩展、翘曲、断裂和剥落往往无法分辨。为了准确判断涂层失效的临界点,提出一种利用应变诊析膜基系统失效临界点的方法。利用双面胶作为粘结剂,2024铝合金为基体,304不锈钢箔为涂层构建膜基系统理论模型,采用PVDF贴片传感器技术研究了脉冲激光作用下不同理论模型涂层表面的动态应变。结果表明:脉冲激光作用下,涂层表面的动态应变不断往复变化,最终趋于平衡,整个过程在微秒量级的时间内完成。同时,涂层表面的动态响应与膜基系统界面结合状况有关,膜基系统结合完好时,涂层表面的动态响应时间长,得到的最终应变量小。膜基系统全完脱粘时,涂层表面的动态响应时间短,最终应变量大,膜基系统刚开始脱粘的试样介于两者之间。
In the process of discrete laser pulse scratches, laser shock wave dynamic loading and interface failure are completed in an instant. It contains the debonding, crack growth, warping, cracking and peeling often can not tell. In order to accurately determine the critical point of coating failure, a method of using strain analysis to diagnose the critical point of membrane-based system failure is proposed. Using double-sided adhesive as a binder, 2024 aluminum alloy as the substrate, 304 stainless steel foil as the coating to build a membrane-based system theoretical model, using PVDF patch sensor technology to study the dynamic strain of the different theoretical model coating surface under pulsed laser. The results show that under the action of pulsed laser, the dynamic strain on the surface of the coating continuously changes reciprocally and finally tends to balance. The whole process is completed in the order of microseconds. At the same time, the dynamic response of the coating surface is related to the bonding condition of the film-based system interface. When the film-based system is in good condition, the dynamic response time of the coating surface is long and the final strain is small. When the film-based system is completely debonded, the dynamic response time of the coating surface is short and the final strain is large, and the sample that the film-based system just begins to debond is between the two.