高强度铝合金腐蚀损伤检测实验研究

Detection of Pit-corrosion Damage in High Strength Aluminum Alloy

在实验室环境下对LC4铝合金进行加速腐蚀试验,用超声C扫描机对试件表面腐蚀损伤特性进行检测,可明显识别单蚀坑及多蚀坑连通区域。用数码显微镜观测单蚀坑表面形貌近似为一个圆形,而且在一个尺寸较大主蚀坑边缘还有若干次蚀坑,首次采用激光位移传感器测量腐蚀坑深度,综合多种测量结果,进行腐蚀损伤形貌研究,经过统计分析点蚀最大坑深度服从威布尔分布。扫描蚀坑断面,按步长获取蚀坑截面坐标值,绘制蚀坑断面二维图形。

Accelarated corrosion tests of LC4 high strength aluminum alloy were performed in the laboratory environment,and corrosion damage information were obtained by using a variety of testing methods.Characteristics of corrosion damage on specimen surface were detected by using ultrasonic C-scanning system,and the single pit and connected regions of multiple pits were obviously recognized.Surface morphology of the single pit was approximate to a circular under a digital microscope,and a large pit was surrounded by several little pits.The depths of etch pits were measured by using laser displacement sensor.Studies of corrosion damage morphology were carried out based on a comprehensive analysis.Max depths of pits obeyed the Weibull distribution.Cross sections of pits were scanned,and the coordinate values were obtained by equal step method.Finally two dimensional drawings of the cross sections were plotted.