基于激光超声的铝合金组织性能无损检测研究

Nondestructive testing of microstructure and properties of aluminum alloy based on laser ultrasound

目前对铝合金析出相和力学性能的检测主要采用扫描电镜(SEM)、透射电镜(TEM)、万能试验机等方式,费时费力且属于破坏性检测。采用激光超声无损检测技术对Al-Cu-Mg铝合金进行检测,通过变分模态分解法(Variational Modal Decomposition,VMD)对时域下的激光超声信号进行降噪处理,得到激光超声信号的衰减系数和声速等特征值,同时采用扫描电镜、电子背散射衍射(EBSD)、静拉伸实验获得Al-Cu-Mg铝合金的析出相和力学性能,将激光超声信号特征值与Al-Cu-Mg铝合金的析出相和力学性能进行耦合。结果发现:激光超声信号特征值与Al-Cu-Mg铝合金的析出相、晶粒尺寸、屈服强度以及显微硬度有较好的相关性。这为Al-Cu-Mg铝合金的微观组织和力学性能快速无损检测提供了一种新方法。

At present,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)are mainly used to detect the precipitated phase and mechanical properties of aluminum alloy,which is time-consuming and laborious and destructive.In this paper,the laser ultrasonic nondestructive testing technique was used to detect Al-Cu-Mg aluminum alloy.By means of Variational Modal Decomposition(VMD),the noise reduction of the laser ultrasonic signal in the time domain is processed,and the attenuation coefficient and sound velocity of the laser ultrasonic signal are obtained.The precipitated phase and mechanical properties of Al-Cu-Mg aluminum alloy were obtained by SEM,electron back scattering diffraction(EBSD)and static tensile test.The laser ultrasonic signal characteristic values were coupled with the precipitated phase and mechanical properties of Al-Cu-Mg aluminum alloy.The results show that the characteristic value of laser ultrasonic signal has a good correlation with the precipitated phase,grain size,yield strength and microhardness of Al-Cu-Mg aluminum alloy.This provides a new method for rapid nondestructive testing of microstructure and mechanical properties of Al-Cu-Mg aluminum alloy.