基于高温EMAT铁磁性材料的声速变化规律研究  

Study on the variation of sound velocity based on high temperature EMAT ferromagnetic materials

作　　者：赵帅杰 张吉堂[1] 周俊峰 岳雯溁 周进节[1] 郑阳[2] ZHAO Shuaijie;ZHANG Jitang;ZHOU Junfeng;YUE Wenying;ZHOU Jinjie;ZHENG Yang(School of Mechanical Engineering,North University of China,Taiyuan 030051,China;China Special Equipment Inspection and Research Institute,Beijing 100029,China)

机构地区：[1]中北大学机械工程学院,山西太原030051 [2]中国特种设备检测研究院,北京100029

出　　处：《中国测试》2022年第9期1-6,共6页China Measurement & Test

基　　金：国家自然科学基金(62071433)。

摘　　要：被检材料温度的变化会影响超声体波的传播速度,进而影响高温测厚和探伤的准确性。针对这一问题,首先采用电磁声换能器(EMAT)测量从室温到850℃下两种铁磁性材料的厚度,得到横波和纵波的声速变化规律。其次研究横波声速变化与弹性模量、热膨胀和质量密度三个因素有关,得出弹性模量是横波在铁磁性材料中的传播速度随温度升高而逐渐减小的主要影响因素。然后建立在居里温度点之上横波消失、纵波出现的力学模型,并得出随着温度升高纵波速度保持不变、幅值先增加后减小的变化规律。最后得出铁磁性材料在居里温度点之后超声波消失与磁畴的无序状态有关。The change of material temperature will affect the propagation velocity of ultrasonic body wave, and then affect the accuracy of high temperature thickness measurement and flaw detection. To solve this problem,the thickness of two ferromagnetic materials from room temperature to 850 ℃ was measured by electromagnetic acoustic transducer(EMAT), and the variation law of sound velocity of s-wave and p-wave was obtained. Secondly, the change of s-wave sound velocity is related to elastic modulus, thermal expansion and mass density, and it is concluded that elastic modulus is the main factor affecting the decrease of s-wave propagation velocity in ferromagnetic materials with the increase of temperature. Then, a mechanical model of s-wave disappearing and p-wave appearing above Curie temperature point is established, and the velocity of pwave remains unchanged with the increase of temperature, and its amplitude increases first and then decreases.It is concluded that the disappearance of ultrasonic wave of ferromagnetic materials after Curie temperature is related to the disordered state of magnetic domain.

关 键 词：超声体波 EMAT 高温检测 铁磁性材料 

分 类 号：TG115.28[金属学及工艺—物理冶金] TB9[金属学及工艺—金属学]