关键词: 涂层结构, 超声检测, 声弹性特征, 增材制造, 材料分布

Abstract: Considering the increasing industrial applications of metal additive manufacturing, it was important to analyze residual stress caused by forming processes and detect residual stress with ultrasonic nondestructive testing, and in coating structure, the complex distribution of materials made the local acoustic elastic characteristics uncertain, resulting in a certain detection errors. Thus, after analyzing the distribution of materials, the stress inversion model of coating structures was proposed. Firstly, the propagation of ultrasound and related ultrasonic signals was analyzed based on the acoustic elasticity theory in variable distributions of materials and stress. Then, considering the forming processes of different coating structural areas in the plasma spray welding additive processes, the distribution of materials in coating structure was discussed. Analyzing the relationship between the acoustic-elastic characteristics and material distribution in bonding area, the stress inversion model of coating structural areas was presented. Finally, the coating structure samples of base material(C45E4) and coating material(Cu) were designed and prepared by plasma spray welding, the ultrasonic testing with tensile/compressive stress was given. Comparing the testing results and calculation ones, the stress inversion model of coating structure is effective. After discussing the feasibility in stress ultrasonic testing, the proposed method is considered as the potential tool in the quality evaluation and monitoring for coating structures.

Key words: coating structure, ultrasound detection, acousticelastic characteristic, additive manufacturing, material distribution