INFLUENCE OF HEAT TREATMENT ON THE COMPRESSIVE STRESS EFFECT OF MAGNETOSTRICTION OF <112> AXIAL ALIGNED Tb-Dy-Fe ALLOYS

The magnetostrictive properties of <112> axial aligned Tb0.3Dy0.7(Fe1-xMx)1.95(M=Mn, Al, x=0～ 0.15) alloys prepared by directional solidification are reported. The influence of heat treatment on microstructure and the compressive stress effect of magnetostriction is discussed.

Influence of Magnetic Heat Treatment and Compressive Stress on Jump Effect of Magnetostriction of Tb_(0.3)Dy_(0.7)Fe_(1.95) Alloy

The 〈 110 〉 -oriented TTb0.3Dy0.7Fe1.95 polycrystalline alloy was magnetically annealed, and its influence on jump effect of magnetostriction was investigated. In the vacuum superconductive high magnetic field equipment, 〈 110 〉 -oriented Tb0.3Dy0.7Fe1.95 polycrystalline alloy of the directional solidification was annealed at 623 and 723 K for 5 min under the magnetic field vertical to specimen axis. It is found that magnetic annealing can enhance the jump effect under compressive stress, and increase the saturated magnetostriction coefficient λs, the λs of the magnetic annealing specimens at 623 K under 8.1 MPa is attained to 1950 × 10^-6, Magnetic annealing increases the maximum of dynamic magnetostriction coefficient, d33^max, as well as the magnetic field for d33^max under 8.1 MPa.

磁场热处理和预压力对Tb_(0.3)Dy_(0.7)Fe_(1.95)合金磁致伸缩“跳跃”效应的影响

研究了磁场热处理对<110>取向Tb0.3Dy0.7Fe1.95多晶合金磁致伸缩“跳跃”效应的影响。在真空超导体强磁场装置中,将经定向凝固的<110>取向Tb0.3Dy0.7Fe1.95多晶合金棒,沿垂直轴向施加强度为1T的磁场,加热到623和723K下,保温5min后随炉冷却。研究结果表明,磁场热处理增强预压力下的“跳跃”效应,提高不同预压力下的饱和磁致伸缩系数λs,其中623K磁场热处理样品在8.1MPa下的λs达到1950×10-6。磁场热处理提高预压力(8.1MPa)下的动态磁致伸缩系数最大值d3m3ax,但同时增大d3m3ax对应的磁场。

压缩应力下(Tb、Dy)Fe_2磁致伸缩的研究

本文利用自制的磁致伸缩测量仪和“ｊｕｍｐ”效应测量仪研究了在一定压强了多晶（Ｔｂ、Ｄｙ）Ｆｅ２棒的磁致伸缩，发现加压时，在一定工艺条件下制作的（Ｔｂ、Ｄｙ）Ｆｅ２棒会有磁致伸缩的变化。卸载后经过热处理，磁致伸缩值在不加压时也会维持一个高值。

制备具有“跳跃效应”Terfenol-D的研究

利用浮区法和布里奇曼法制备Ｔｂ０．３Ｄｙ０．７Ｆｅ１．９５的Ｔｅｒｆｅｎｏｌ－Ｄ，通过磁致伸缩系数的测定，发现利用浮区法制备的样品在一定的压应力下有“跳跃效应”，利用布里奇曼法制备的样品具有较大的压力效应但没有出现“跳跃效应”。通过Ｘ射线衍射、劳埃背反射发现，浮区法制备的Ｔｂ０．３Ｄｙ０．７Ｆｅ１．９５是孪生单晶，并且具有明显的取向，在一定工艺条件下用布里奇曼法制备出的样品不是单晶。