分析了材料组分、密度对射线衰减系数的影响，介绍了基于组分特性的材料密度工业X射线CT定量无损检测方法——线衰减系数对比法。以铝合金标准样品密度定量检测为例，研究了X射线“等效能量”的获取方法，建立了“等效能量”下CT值和线衰减系数的对应关系。通过线衰减系数和质量衰减系数实现了对铝合金材料密度的定量检测。试验研究表明，对于密度均匀的铝合金材料，基于组分特性的线衰减系数对比法测试精度明显优于密度对比法。

In this paper, the line attenuation coefficient affected by material composition and density was analyzed, the quantitative NDT method of materials density and the line attenuation coefficient comparison method based on materials composition by industrial X-ray computed tomography was described. As examples, the test method for X-ray CT systems equivalent energy measurement for some homogeneous aluminum alloy standard samples was studied, and the correlation of the CT value and the line attenuation coefficient at the equivalent energy was presented. With the help of the line attenuation coefficient and mass attenuation coefficient, the aluminum alloy materials densities could be determined. The experiment results showed that the measurement accuracy of density with the line attenuation coefficient comparison method based on materials composition characteristics was obviously better than density comparing method.