(西安赛特金属材料开发有限公司，西安 710021)
摘 要: 为解决小规格钛合金棒材在超声波探伤中成分偏析类缺陷的判定问题，采用超声波无损检测、金相观察、扫描电镜和能谱分析等方法研究小规格TC4和TC26两类钛合金棒材的成分偏析现象。结果表明：TC4的偏析缺陷是纯钛偏析，缺陷回波出现在底波和等边三角波之间，强度较低，属于透射类偏析；TC26的偏析缺陷是富铌偏析，缺陷回波出现在底波之前，且强度较高，属于反射类偏析。根据成分偏析部分与基体声阻抗的差别对缺陷进行分类，透射类缺陷差别较小，反射类缺陷差别较大。为避免漏检可能存在的透射类成分偏析缺陷，应关注一次底波与等边三角波之间的波形
关键字: 钛合金；成分偏析；超声波检测；反射；透射
small diameters titanium bars
（Xi’an SMA Materials Co., Ltd., Xi’an 710021, China）
Abstract:To classify the defects of composition segregation in titanium alloy bars with small diameters by ultrasonic inspection, the defects in TC4 and TC26 titanium alloys were characterized by methods of ultrasonic inspection, metallographic analysis, SEM and energy spectrum analysis. The results show that pure titanium segregations in TC4 titanium alloys, as indicated by the wandering echo between the primary bottom wave and equilateral triangle wave, are categorized as penetrating defects. By contrast, the Nb-riched segregations in TC26 titanium alloys belong to reflection defects that are characteristic of a high-amplitude wave in front of the primary bottom wave. The categorization of the defects of composition segregation is obtained by the variation of acoustic impedance between the parent material and segregation areas, where the variation of penetrating defects is similar while that of reflection defect is different completely. In order to avoid the undetected cases of penetrating defects, it is important to observe the echo waves that may appear between the primary bottom wave and equilateral triangle wave.
Key words: titanium alloy; composition segregation; ultrasonic inspection; reflection defect; penetrating defect
