Melt Spinning Procedures for Optimization of Terbium-Dysprosium Alloy Transducers

The discovery of the large magnetostriction in Terbium-Dysprosium alloys at liquid nitrogen temperatures has created the possibility of constructing high performance transducers for Naval applications. Before such transducers are made this stris of the alloy with the proper crystalline orientation which maximizes the anisotropic magnetostrictive behavior must be manufactured. An innovative and novel appraoch using a melt spinning technique is proposed. With this approach it is believed that the cooling rate in the ribbons can be adequately controlled to generate a columnar microstructure of hemagonal crystals with the o axis oriented along the thickness of the melt spun ribbons. The m or b axis, the axis of maximum magnetostriction, will be aligned along the length or width of the ribbon allowing the ribbon to be stacked to form a very sensitive magnetostrictive transducer. This is contrasted to conventional melt spinning methods where the existence of thermal gradients in the ribbons limits the degree of orientation. The degree of optimal orientation can be further enhanced and controlled by appropriate additional processing.