LC9铝合金是航空航天领域主要的结构材料，该材料传统的检测方法都是建立在对材料有损害的基础上进行的，且存在试验周期长、取样范围有限等缺点，尤其不适合现场检测。该试验以经过固溶处理的LC9铝合金作为研究对象，通过试验分析了不同时效状态下显微组织与超声波速率的关系。结果表明: 不同的超声波速率对应不同的显微组织，在其他材料的组织性能检测中，也可用超声波检测来判断其显微组织。

LC9 aluminum alloy is the primary structure material in the field of aeronautics and astronautics. The traditional detection methods of this material are all based on damage to the material, and have the disadvantages of long experimental cycle and limit sampling area. Thus they are especially not suitable for on-site inspection. LC9 aluminum alloy after solid solution treatment was chosen as the research object in the experiment. The relationship between the microstructure and ultrasonic velocity of LC9 aluminum alloy under different aging condition was analyzed through testing. The results show that the ultrasonic velocity varied corresponding to different microstructure. The ultrasonic detection could be used to determine the microstructure of other materials.