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基于超声无损检测的扩散连接界面缺陷尺寸评估

Evaluation on interfacial defect size of diffusion bonding based on ultrasonic non-destructive testing

  • 摘要: 针对扩散连接界面缺陷的无损检测问题,开展了人工缺陷试样的水浸超声检测试验研究,提出了扩散连接界面缺陷超声响应模型,开发了一种通过超声检测评估界面缺陷厚向尺寸的检测手段. 首先利用扩散连接的方法制备了带有人工缺陷扩散连接试样,采用30 MHz的入射波频率,对试样进行水浸超声无损检测. 基于超声无损检测原理提出了未焊合缺陷的超声响应模型,引入扩散连接界面劲度系数K作为桥梁建立起超声反射波反射率与界面缺陷尺寸之间的联系. 通过特定检测位置的超声反射波数据和实际微观缺陷尺寸数据拟合确定超声响应模型常数,进而实现基于超声无损检测的界面缺陷厚向尺寸评估. 结果表明,传统超声C扫描一般只是定性地反映缺陷存在与否,而厚向尺寸评估方法的提出在一定程度上为超声C扫描做了补充,有助于缺陷尺寸的定量检测,实现缺陷危害等级的评估.

     

    Abstract: Aiming at the non-destructive testing problems of interfacial defects of diffusion bonding, the water immersion ultrasonic testing was performed on the prepared specimen with artificial defects. An ultrasonic response model of interfacial defects of diffusion bonding was proposed. A measurement method was developed to evaluate the interfacial defect thickness by ultrasonic testing. The specimen with artificial defects was firstly prepared by the diffusion bonding process. It was later subjected to the water immersion ultrasonic testing through an incident wave frequency of 30 MHz. Based on the principle of ultrasonic non-destructive testing, an ultrasonic response model for unbonded defects was proposed. The interfacial stiffness coefficient (K) was introduced as a bridge to establish the relationship between the ultrasonic reflectivity and the interfacial defect size. At the specific measurement position, constants of the ultrasonic response model were determined by fitting the ultrasonic reflected wave data and actual micro defect size. Therefore, the interfacial defect thickness can be evaluated by the proposed model based on ultrasonic non-destructive testing. The results show that tradition ultrasonic C scanning usually determines qualitatively whether the defects exist or not. The proposed measurement method of interfacial defect thickness make a supplement for ultrasonic C scanning to some extent. It is helpful for measuring defect size quantitatively. The evaluation of defect risk level is achieved.

     

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