Acoustic emission defectoscopy of paratellurite crystals

The possibilities of using the acoustic emission (AE) method for evaluating the defectivity of TeO$_2$ paratellurite crystals in the process of their elastic-plastic deformation have been investigated. A series of experiments on compression to fracture of paratellurite crystals samples of 6 $\times$ 6 $\times$ 12 mm in size with registration of AE pulses in the process of loading has been carried out. It is shown that time dependences of primary AE-parameters do not allow to unambiguously determine the structural-mechanical state and the presence of defects in the studied crystals, and a detailed analysis of acoustic signal parameters is required. The most informative AE parameters indicating the formation of crack-like defects have been identified. To establish the possibility of defects detection, the empirical distribution functions of AE pulse duration registered in the process of crystal loading have been constructed. It is shown that the value of the high-level quantile of the empirical distribution function of AE pulse duration can be used as a criterion parameter for establishing the moment of defect formation in the crystal. Its threshold value indicating the occurrence of irreversible damage has been established.