Qiao Rui, Yan Xiaoling
School of Artificial Intelligence, Beijing Technology and Business University, Beijing 102488, China.
Materials (Basel). 2022 Jan 18;15(3):718. doi: 10.3390/ma15030718.
Fatigue damage is the main reason for the failure of parts formed by selective laser melting (SLM) technology. This paper presents a high-order, harmonic, and nonlinear ultrasonic testing system for monitoring the generation and evolution of fatigue damage in SLM 316L stainless steel parts. The results demonstrate that the normalized ultrasonic, nonlinear coefficients show a significant dependence on the degree of fatigue damage of the tested specimen and that the normalized, ultrasonic, and nonlinear coefficients are effective in characterizing the degree of fatigue damage in SLM 316L stainless steel parts. Transmission electron microscope (TEM) and scanning electron microscope (SEM) analyses show that the variation in the normalized, ultrasonic, nonlinear coefficients reflect the generation and evolution process of dislocation and crack in the fatigue process of SLM 316L stainless steel specimens, and reveal the fatigue damage mechanism of SLM 316L stainless steel parts.
疲劳损伤是选择性激光熔化(SLM)技术成型零件失效的主要原因。本文提出了一种用于监测SLM 316L不锈钢零件疲劳损伤产生与演变的高阶、谐波和非线性超声检测系统。结果表明,归一化超声非线性系数对被测试样的疲劳损伤程度有显著依赖性,且归一化超声非线性系数能有效表征SLM 316L不锈钢零件的疲劳损伤程度。透射电子显微镜(TEM)和扫描电子显微镜(SEM)分析表明,归一化超声非线性系数的变化反映了SLM 316L不锈钢试样疲劳过程中位错和裂纹的产生与演变过程,揭示了SLM 316L不锈钢零件的疲劳损伤机制。