MAGNETOMECHANICAL DAMPING CAPACITY OF ⟨110⟩ ORIENTED Tb0.36Dy0.64(Fe0.85Co0.15)2 ALLOY

During the mechanical loading and unloading process, Tb-Dy-Fe, giant magnetostrictive materials can dissipate a mass of elastic energy due to the irreversible movements of non-180 degrees domain walls, which is of interest to be applied in passive damping control systems. The magnetomechanical damping capacity of Tb-Dy-Fe compound is strongly sensitive to the stress magnitude as well as the external magnetic fields. As a new member of the Tb-DY-Fe family, quaternary Tb0.36Dy0.64(Fe0.85Co0.15)(2) compound has been developed as a good candidate in wide Operating temperature range applications. In order to realize the application of Tb0.36Dy0.64(Fe0.85Co0.15)(2) compound in passive damping control system, it is important to systemically investigate its damping capacity under coupled magnetomechanical loadings. In the present work, < 110 > oriented Tb0.36Dy0.64(Fe0.85Co0.15)(2) crystal was prepared with a growth velocity of 480 mm/h by zone melting directional solidification method. The damping capacity was studied by quasi-static stress-strain measurements under a series of constant magnetic fields up to 0.325 T. Stress ranges from 0 to -10, -30 and -50 MPa were used at room temperature. The results show that maximum damping capacity (Delta W/W) is obtained at zero field. Under certain stress amplitude sigma(m), Delta W/W decreases with the increase of magnetic field. A critical magnetic field exists in the damping capacity-magnetic field (Delta W/W-H) curves, and seems independent oil the stress magnitude. Under coupled magnetic-stress loadings, the magnetostriction-magnetization curves were measured to analyze the switching process of domains and movements of domain walls, by which an explanation on the variation of damping capacity was given.