超声作用下树脂基磁致伸缩复合材料的制备及其性能

Preparation of magnetostrictive composites using ultrasonic and their properties

树脂基磁致伸缩复合材料是由Terfenol-D颗粒分散在树脂基体内形成的一类复合材料,颗粒的分散均匀性以及颗粒与基体界面的粘结紧密性是影响其性能的两个重要因素。由于颗粒与基体润湿性差,机械搅拌制备的磁致伸缩复合材料,普遍存在分散不均,孔隙率高等缺点。高强度超声在液态树脂中传播时,会产生空化、声流等非线性声学效应,对促进颗粒分散和改善固液界面具有一定的作用。以环氧树脂为基体,分别采用机械搅拌法和高能超声法制备了Ter- fenol-D颗粒体积含量为50%的树脂基磁致伸缩复合材料。对两种材料进行了SEM分析及力学和磁致伸缩性能测试。实验结果表明,较之机械搅拌法,超声分散法制得的磁致伸缩复合材料具有颗粒分散均匀,孔隙率低,颗粒与基体的界面结合性好,弹性模量高,磁致伸缩应变大等优点。

Polymer-bonded Terfenol-D composites are maily composed of Terfenol-D particles and polymer matrix, uniformity of Terfenol-D particles and boundary condition of interface between the particles and matrix are two important factors which influence their performance. Due to bad infiltration between particle and matrix, the polymer-bonded Terfenol-D composites made by mechanical dispersion method are universally possessing defects of non-homogeneous particles distribution and worse interface between particles and matrix. Using ultrasonic instead of mechanical dispersion is a potential way to solve those problems because of the cooperative effects of acoustic cavitation and high speed acoustic stream in liquid resins. In this paper, two epoxy-bonded Terfenol-D composites with 50 % particle volume fraction were fabricated by mechanical dispersion and ultrasonic dispersion methods, respectively. The results obtained by microstructure analysis revealed that the composites prepared by ultrasonic have compact structure and homogeneous distribution of particles. Furthermore, the examination of mechanical properties and magentostrictive properties indicated that using ultrasonic dispersion method can improve both the elastieity module and magnetostriction of magnetostrictive composites.