Abstract:

The giant magnetostrictive terbium-iron alloy material, Terfenol-D, offers the highest strain of any magnetostrictive material at room temperature using practical drive fields. The increasing use of Terfenol-D in a wide variety of production devices and systems has driven the development of new, advanced manufacturing techniques in material production to provide greater strain performance, uniformity, rod size, and production capacity. As more applications for this smart material are developed, the demand for reliable design data to enable applications engineers to take advantage of Terfenol-D's superior properties has also grown. Recent developments in production techniques have made strides to fulfill needs in both areas. The ETREMA crystal growth (ECG) system, based on the modified Bridgman process, is capable of producing larger rod sizes (65-mm diameter and 175-mm length) with greater quality control, performance, material homogeneity, and uniformity. These improvements are quantified with material property data. Terfenol-D samples are characterized in a transducer under a wide variety of real-world operating conditions. Results show greatly improved consistency of material performance, in terms of material properties, from test to test.