Ultrasonic vibration system is the latest technology discovered for grain refinement process of lightweight metal industries. The introduction of ultrasonic vibration into molten metal just before onset of solidification are found to induce cavitations enhanced nucleation and cavitations enhanced dendrite fragmentation, where both mechanism lead to grain refinement in metals.
This interim report provides an insight of this thesis progress over Semester 1, 2013. This thesis main objective is to design, develop and test a high power ultrasonic system that can generates high intensity sonic excitation for liquid metal from outside the mould wall during a grain refinement treatment procedure. This project is divided into 3 stages: literature review, ultrasonic system project design and project testing methodology.
The literature review would focus on the thesis related topics which are grain refinement, solidification of metal and ultrasonic vibration. This stage of the report also present the current status of grain refinement of light weight metals, specifically on techniques involving ultrasonic excitation during metal solidification process. The ultrasonic system design involves the development of project model, engineering analysis on the model, system technical specifications, system control range, model drawings and procurement of each design component. This stage also cover a simple heat transfer analysis of temperature loading of major components involve in the design as well as proposal of technique for investigation of penetration depth of high-intensity mould wall excitation into liquid metal. The final stage of this thesis focuses on testing of the newly built ultrasonic system. This stage involves designing a laboratory scale testing for the system, as well preparing lab induction and risk assessment for the testing. The outcome of this final stage will be use to assess the potential of the new system as application for larger industrial scale.