This Small Business Innovation Research Phase I project entitled "USV-Grain Refining" aims at advancing the grain refining technologies for the production of aluminum or magnesium alloy ingots or castings. Grain refining is usually one of the first processing steps for the production of metal and alloy products. The conventional methods use chemical grain refiners that contain foreign particles. These methods have limited capability in reducing grain size, and foreign particles added into molten metals lead to defect formation during materials processing. This project will combine the latest technologies of processing of lightweight materials using ultrasonic vibration (USV) and continuous casting or direct chill casting technology, and to demonstrate the feasibility of an enabling technology for producing metal ingots of ultrafine grains without the use of foreign particles for grain refining. The new technology will provide cost effective opportunities for producing metal and alloy products with grain size much smaller than that obtainable using the best commercial grain refiners, addressing issues related to the defect formation associated with the use of grain refiners containing foreign particles and increasing the production rates of metals and alloys. The successful completion of this Phase I project will lead to a breakthrough technology for grain refining of a vast array of metals and alloys to the grain size level that are not capable to achieve using the conventional technologies. Grain refining is important for maximizing ingot casting rate, improving resistance to hot cracking, minimizing elemental segregation, enhancing mechanical properties, particularly ductility, improving the finishing characteristics of wrought products, increasing the mold filling characteristics, and decreasing the porosity of foundry alloys. The commercial implementation of the project results has the potential of achieving significant cost savings, energy savings, and environmental benefits for the metal manufacturing industry. In addition, students involved in the research will have opportunities to interact with industrial partners. This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).