Investigation of acoustic emission due to deformation of titanium alloy and some results of acoustic-emission diagnostics of its predestruction states

The paper presents acoustic-emission (AE) characteristics of the Ti-Al-Mo-Si alloy. The energy of one AE event has been estimated over the entire frequency band under investigation. AnS-shaped curve of the logarithm of the frequency of AE events plotted against the strain has been obtained, and the physical interpretation of such a dependence has been given. A tentative explanation of the delay of AE events on the initial stage of the material deformation with a stress concentrator has been suggested. On the base of the correlation between the service-life expectancy and the frequency of AE events, which has been established in our experiments, the degree of confidence in the diagnostic data concerning the predestruction state of gas-turbine blades in turbojet aircraft engines has been estimated.