University: University of Nottingham. Supervisor: Prof. Richard Smith, Prof. Matt Clark. Sponsor: IHI. Contact: Richard.J.Smith@nottingham.ac.uk Start date: October 2019
Advanced engineering alloys are used in many high value, high performance industries. The design of alloys with specific properties and processing routes to obtain the ‘right’ microstructure for the part is incredibly important for increasing the capabilities of materials to meet the emerging needs of industry. One method for mapping the microstructure is spatially resolved acoustic spectroscopy (SRAS); this technique maps the variations in surface acoustic wave velocity to obtain the crystallographic orientation. The resolution of SRAS microscopy is currently limited by two factors to around 1/25th of optical resolution (practically) and 1/10th of the optical resolution (theoretically).
In this project we will explore two techniques that can address these factors with the aim of developing an alternative strategy and instrumentation design that will allow SRAS to access the full optical resolution (<1um). The first is to switch the instrumentation away from the current pump-CW detection systems we use to pump-probe. This will raise the instrumentation defined limit of the maximum frequency we can use from around 300MHz to (effectively unlimited) 100GHz. The second is to attempt to perform the measurement using high frequency axial propagating bulk waves rather than the surface waves we currently use – this can only be performed at very high frequencies in the 20-100GHz range.