基于激光声表面波的硬脆材料加工表面/亚表面残余应力检测理论与方法研究

硬脆材料以其独特的机械、力学及光电性能在航空航天、国防等高新技术领域广泛应用。其精密和超精密加工表面残余应力的定量检测是表面完整性研究领域有挑战性的课题。课题基于材料弹性力学、塑性力学及非线性声学传播理论，研究激光表面波在加工表面/亚表面应力层传播机制；建立反映加工表面特性、加工表面残余应力状态及所带来的频散及衰减的声表面波非线性传播模型；研究声表面波非线性传播特征反演带损伤标定残余应力的算法；提出求解瞬态声表面波时频多尺度速度和能量衰减的新方法；通过改进设计搭建基于外差式激光干涉仪的激光声表面波检测平台，实现硬脆材料加工表面/亚表面残余应力的纳米级定量检测；通过与X射线衍射仪、纳米压痕仪进行对比测试，验证该检测系统测量结果的可靠性。本研究作为硬脆材料加工表面/亚表面残余应力的定量检测提供可靠手段，对实现加工表面完整性定量评价及提高其零件的使役性能有着重要的理论意义和工程应用价值。

Hard-brittle materials are widely used in the aerospace, national defense and other high-tech fields for their unique mechanical properties and optoelectronic properties. The quantitative detection of its surface residual stresses generated by precision and ultra-precision machining is taken as a challenging subject in the field of surface integrity research. In this project, based on material elastic mechanics, plastic mechanics and nonlinear acoustic propagation theory, the propagation mechanism of Laser Generated Surface Acoustic Wave (LSAW) in the layer of machined surface/subsurface stress layer will be researched; establish the LSAW nonlinear propagation model which reflects the machined surface characteristics, the residual stress state of the machined surface, and the dispersion and attenuation effect; study the algorithm of residual stress with damage calibration inversion based on the nonlinear propagation characteristics of LSAW and a new method for solving time-frequency multi-scale velocity and energy attenuation of transient LSAW; by improving the design of LSAW detection platform based on heterodyne laser interferometer, the nano-scale quantitative detection of surface/subsurface residual stress of hard-brittle materials will be realized; verify the reliability of the measurement results of the detection system by comparison with results of X-ray Diffractometer and Nano-indentation. This work provides a reliable means for the quantitative detection of surface/subsurface residual stress of hard-brittle materials. And it has important theoretical significance and practical application value for the quantitative evaluation of machined surface integrity and improving the service condition of its parts.