本文用标准应变片法研究了Ｔｂ０．２７Ｄｙ０．７３Ｆｅ１．９８在压应力下的磁致伸缩特性，由于样品中存在多个晶粒，所以没有发现“巴克豪森跳跃”现象，但是λ－Ｐ曲线却表现出了一定的规律性：在低场下曲线单调下降，当Ｈ＝５０ｋＡ／ｍ时在Ｐ０＝１３．６ＭＰａ处曲线开始出现一峰值，且Ｐｏ不随外场的增加而变化。文中用自由能极小原理对这一现象作了诠释，发现Ｐ０与样品的各向异性场Ｈａ成正比：Ｐ０＝μ０ＭｓＨａ３λ In this paper, the magnetostrictive behavior of Tb0.27Dy0.73Fe1.98 under compressive stress was studied by using standard strain gage method. Because of the existence of multiple grains in the sample, no “Barkhausen jump” phenomenon was found, but the λ-P curve But the curve shows a certain regularity: the curve decreases monotonously at low field, and a peak starts to appear at P0 = 13.6MPa when H = 50kA / m, and Po does not change with the increase of external field. In this paper, we use the principle of free energy to interpret this phenomenon, and found that P0 is proportional to the anisotropy field Ha of the sample: P0 = μ0MsHa3λ