Thermographic analysis of the fatigue heating process for AZ31B magnesium alloy: Fid-Bau Portal

Thermographic analysis of the fatigue heating process for AZ31B magnesium alloy

Guo, Shaofei / Zhou, Yaguo / Zhang, Hongxia / Yan, Zhifeng / Wang, Wenxian / Sun, Kun / Li, Yuanda

Highlights • The heating process of AZ31B under fatigue was studied by thermography method. • The temperature measurement area was extended to almost the entire specimen surface. • The relationship between temperature field and stress distribution was discussed. • A modified way was proposed to estimate the fatigue limit of AZ31B more readily.

Abstract Infrared thermography coupled with a special image processing was employed to study the heating process of AZ31B magnesium alloy during the high-cycle fatigue process. Heat-conduction effect was subtracted from thermal data provided by an infrared camera to study the heat-dissipation rate evolutions. Three stages of temperature variation were observed before the initiation of macroscopic crack, when the stresses were above the fatigue limit and below the yield limit. Severe work-hardening effect led to a drastically degradation in plastic deformability, and also caused the heat-dissipation rate dropped steeply from the maximum to the saturation value. The correlation between temperature distribution and stress distribution was also investigated. At different stress level, the temperature distributions in a single sample are different. Finally, an improved graphical method was proposed to estimate with good approximation of the fatigue limit of AZ31B magnesium alloy more readily. The proposed method showed basically satisfied results comparing with the conventional method.