Ultrasonic Characterization of State and Properties of Aluminium Structures

The contribution gives a short overview of the ultrasonic investigations to characterizae microstructure and to evaluate mechanical properties, performed at the IZFP and shows the possibilities of their use for process control. The propagation velocities of ultrasonic waves allow the evaluation of the elastic constants of the alloy and good correlations are found between the acousto-elastic constant of different alloys and their yield strengthes. Using the times-of-flight of different ultrasonic waves, the residual stress states in plates and welded parts are evaluated. The texture in Al-sheets is determined and the earing parameter is characterized using measurements of ultrasonic times-of-flight as function of the ultrasonic propagation direction. Ultrasonic backscattering technique is applied to visualize the distribution of ceramic reinforcements in automotive pistons and conrods made of al-based metal matrix composites. The volume content on reinforcement is evaluated from the ult rasonic velocities. Backscattering and time-of-flight measurements are used to visualize and to characterize the burrs in al- hollow castings.