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摘自冶金部钢铁研究总院研究生侯玉敏的硕士学位论文,导师:罗阳 近年来,对Nd_2Fe_(14)B为基的第三代稀土永磁的结构和内禀性质,特别是磁学性质已进行了较广泛而深入的研究,但对其声学性质及与之相关的杨氏模量等弹性性质却研究较少。本文从弹性变化角度出发,研究了Nd_2Fe_(14)B中超声速度/衰减与自旋再取向的关系。实验采用MATEC-6600系列,用超声脉冲回波法测量速度及衰减随温度的变化,升降温速度为0.5 K/min,石英换能器的频率为10 MHz,声速测量中时间间隔的测量精度为0.1 ns,相对精度<10~(-4),衰减测量精度为0.1 dB。
In recent years, the structure and intrinsic properties of the third generation rare earth permanent magnet Nd 2 Fe 14 B, especially the magnetic properties have been carried out A more extensive and in-depth study, but its acoustic properties and related Young’s modulus and other elastic properties are less studied. In this paper, the relationship between the velocity of supersonic / decay and spin reorientation in Nd 2 Fe 14 B is studied from the perspective of elastic change. The experiment uses the MATEC-6600 series. The velocity and attenuation of the MATEC-6600 series are measured by the ultrasonic pulse echo method. The heating and cooling rate is 0.5 K / min and the frequency of the quartz transducer is 10 MHz. The measurement accuracy of the time interval in the sound velocity measurement is 0.1 ns, relative accuracy <10 ~ (-4), attenuation measurement accuracy of 0.1 dB.