Faculty Sponsor's Department:
This research investigates if Resonance Ultrasound Spectroscopy (RUS) offers an effective Non-Destructive Testing (NDT) technique for evaluating precipitation within in a component. Four pizoelectric transducers are used to measure the resonance frequencies, one drive transducer, two receivers, and a dummy transducer for supporting the component. Herein frequency shifts are measured for heat treated Aluminium alloys (7075, 6061, 1000) as they are solution treated, aged, and over aged. Abaqus Finite Element Analysis (FEA) software is being used to model the resonance modes and frequencies, so we can analyse mode specific frequency changes of the sample. Initial work on Al alloy 7075 indicates that homogenizing the alloy to a solid solution of α-aluminium results in a global drop in resonance frequencies for all resonance modes. In general, aging is seen to increase resonance frequencies. Hardness data are also being collected to assess how hardness increases and decreases with global resonance changes while aging progresses. This suggests that precipitation strengthening, and eventually weakening from over aging, can be observed from the resonant frequency spectra. Additionally, the elastic modulus will be affected by the proportion of secondary phase precipitates. Future work will investigate Al-6061 (Al-Mg-Si), including Scanning Electron Microscopy (SEM) obtained micro-graphs and Rockwell B hardness tests in order to monitor changes through-out the aging process. These measurements will then be correlated to measured resonance frequency shifts to assess strength changes within the sample as a function of aging.