This award is to research and develop an ultrasonic based sensor for the in-situ monitoring of the precipitation hardening process in materials, in close cooperation with an industrial co- sponsor. This will enable the on-line monitoring and control of heat treatment facilities in aircraft manufacturing plants with improvements in manufacturing efficiency and quality. The basis of sensor design approach is the relationship between sound wave velocity and the elastic moduli and elastic behavior of the material in the proximity of metallurgical reactions, such as precipitation hardening. The development of this sensing capability, in close coordination with a major aerospace manufacturer, will foster a relationship between academic and industry participants, while improving the efficiency of an operation in the manufacturing sector.