扫描电镜下的数字散斑相关方法及其应用

对数字散斑相关方法(digital speckle correlation method,DSCM)在扫描电镜(scanningelectron microscope,SEM)下的应用进行了研究。将DSCM与带电液伺服试验系统的SEM结合起来,对二者结合的过程进行了分析,实现了SEM下细微观变形场的测量,扩展了DSCM和SEM的应用范围。为了定量地把握SEM在扫描图像时放大倍数的不稳定性、非线性和内部噪声对DSCM的影响,还对SEM下的DSCM精度和误差进行了实验分析。统计结果表明,SEM下应用DSCM进行变形场的测量,其位移测量误差最大可达2像素,其精度可以满足一般变形场测量的需要。作为应用实例,对混凝土试件在SEM下的断裂行为进行了研究,得到了混凝土试件表面随着载荷的变化而变化的表面细观变形场。

Digital Speckle Correlation Method and Its Application under SEM

The application of digital speckle correlation method (DSCM) under scanning electron microscope(SEM) is studied in the paper.The process of a combination of the DSCM and SEM with servo is described.And the meso-scale and micro-scale deformation field measurement is implemented.The research extends the application fields of the DSCM and the SEM.In order to quantificationally study the effect of excursion during SEM scanning on the DSCM,the precision and error of the DSCM under the SEM are analyzed experimentally.Results indicate that the displacement error may reach 2 pixels mainly owing to the excursion of the SEM.The error of mechanical system can be enlarged at bigger magnification.And the precision of the DSCM can satisfy the measurement requirement under a SEM at the submicron scale.As illustration,a three point bending experiment of concrete specimen was carried out.The nonuniform deformation fields of concrete specimen under different load were measured in meso-scale.