Noninvasive tracking of solidification using ultrasound

Abstract

Noninvasive tracking of solidification is typically done by monitoring the sample’s surface temperature. This approach is error-prone and not always appropriate for complex geometries and often does not provide complete information on the sample’s transitioning phases. This feasibility study investigates using ultrasonic waves to noninvasively track solidification in wax. Ultrasonic sensors are used in through-transmission mode to monitor the response over the solidification period. The difference in speed of sound between the wax’s liquid and solid phase allows for the solid fraction of the sample to be calculated over the solidification period and the time of complete solidification to be identified. Changes in attenuation during solidification are consistent across experiments. These changes are likely to provide additional information about the cast once they are fully understood. Temperature probes are used to verify the results obtained from the ultrasonic data. The ultimate goal of the project is to use a metal sample and connect information from the ultrasonic signal to the material properties and grain structure of the cast using noninvasive ultrasound technology.