Specific heat and thermal transport measurements of reactive metallic alloys by noncontact calorimetry in reduced gravity

Experimental concepts, application, and recent results: of noncontact calor imetry inculding ac-specific heat and thermal transport property measuremen t of reactive metallic specimens are described. The method is based on indu ction heating in an electromagnetic levitation device. Experiments have bee n performed in reduced gravity onboard Spacelab. A heat flow model is discu ssed regarding conditions for precise specific heat determination from the temperature response to modulated heating power input as well as determinat ion of thermal transport properties fi om the transient temperature respons e. Modulation techniques were developed for application in the metastable r egime of the undercooled melt. where processing time is a critical issue. R esults to be discussed include the total hemispherical emissivity of a bulk metallic glass-forming allo) revealing effects of surface segregation, the rmal conductivity measurements, and application of ac calorimetry in the tw o-phase region.