Laser photoacoustic microscopy of mechanical stresses in modern materials
Аннотация
This paper presents the main experimental and theoretical results so far obtained in the detection of internal stresses by the photoacoustic method in brittle and plastic materials. Examples are presented of typical photoacoustic images of sections of Vickers-indented ceramics and metals. The main assumptions of the nonlinear model of the photoacoustic effect in stressed materials are formulated, taking into account the stress dependence of their elastic and thermoelastic properties. Experimental results are presented that demonstrate how external mechanical stresses affect the photoacoustic images of the indented regions in ceramics and metals. The results of the proposed theoretical model are compared with the experimental data for areas close to the ends of radial cracks in ceramics and the indentation zones in metals.