321不锈钢疲劳早期损伤的涡流评估

摘要

The early fatigue damage of AISI 321 stainless steel was conducted evaluation by eddy current array. In the fatigue test, the change of eddy current amplitude could be divided into three stages: rapid growth, stability and accelerated growth. The relationship between the eddy current amplitude and the logarithmic fatigue life was nearly linear at the first stage. The area of fatigue damage was not changed in the fatigue crack initiation life. Microstructure with different fatigue cycles indicated that the dislocation proliferation and interaction were the main reasons for the increasing of eddy current amplitude at the beginning of fatigue.%采用涡流阵列系统对321不锈钢疲劳早期损伤进行了检测与评估.整个疲劳过程中涡流幅值的变化分为快速增长、稳定和加速增长三个阶段.第一阶段的涡流幅值与循环周次对数之间有近似线性关系.在裂纹萌生寿命内,疲劳损伤区的大小与循环周次无关.对不同循环周次下321不锈钢试样的微结构分析表明疲劳早期涡流幅值变化的主要来源是材料内部位错的增殖和运动,而不是马氏体相转变.