TC4钛合金显微组织对超声波探伤杂波水平的影响

Effect of Microstructures on Noise Level in Ultrasonic Testing of TC4 Titanium Alloy

研究了TC4钛合金显微组织对超声波探伤杂波水平的影响。利用光学显微镜对具有不同超声波探伤杂波水平区域的显微组织进行了对比,研究建立了一种对显微组织不均匀性的表征方法,结合该方法分析了组织与探伤杂波水平的关系。利用电子背散射衍射技术(EBSD)对显微组织不均匀区域进行了晶体取向分析。结果显示,探伤杂波水平较高区域呈现出明显的显微组织不均匀性,结合超声探伤原理分析得出不均匀区域显微组织晶体取向变化是产生杂波的根本原因。此外还对比研究了原始β晶粒尺寸对超声探伤杂波水平的影响,结果表明显微组织界面越多,超声探伤杂波水平越高。

The effect of microstructures on noise level in ultrasonic testing of TC4 titanium alloy was investigated. A comparative study of microstructures for different noise levels was performed using optical microscopy. A new characterization of microstructure inhomogeneity was developed and used to explain the reason for different noise levels. The EBSD technique was used to provide orientation information about these inhomogeneous microstructures. Results show that the region with high noise level presents obvious microstructure inhomogeneity. With the principle of ultrasonic testing, it is concluded that the variation of crystallography orientation would essentially give rise to the noise in ultrasonic testing. Finally ultrasonic response of TC4 alloy with different fl grain sizes was investigated, and it is shown that the specimen with more microstructure interfaces exhibits a higher noise level.