Research on Micro-Crack Detection Technology of Aluminum Alloy Based on Ultrasonic Mixing Nonlinear

Under the action of environmental effect and alternating load, metal material components are prone to fatigue damage and micro-cracks, resulting in fatigue fracture, causing economic losses and even endangering life safety. Therefore, it is very important to study the early fatigue micro-crack detection. It is found that after ultrasonic mixing passes through metal materials containing micro-cracks, obvious nonlinear response will be generated in the received signal. In this paper, 6061 aluminum alloy plate is taken as the research object, the nonlinear coefficient expression of mixing signal is deduced theoretically, and the propagation process of mixing signal in aluminum alloy is simulated by COMSOL. The nonlinear response of micro-crack to mixing received signals is detected. The ultrasonic mixing nonlinear detection system was built, and the ultrasonic mixing nonlinear coefficient was used to characterize the location of micro-cracks, and the feasibility of the ultrasonic mixing micro-crack detection method was verified.