采用等离子喷焊工艺在45#钢基体上制备高铝青铜喷焊层，研究喷焊层的微观组织、相结构、成分及抗热震性能，并探讨热震失效机制。结果表明，基体中的 Fe 元素向喷焊层纵深方向扩散，界面处呈扩散冶金结合特征；喷焊层形成α、γ2及β′相包围k相生长的细小组织，共析体(α+γ2)析出受到抑制，组织韧性较强；经600℃加热淬水的33次热震实验后喷焊层表面仍保持良好；因界面两侧成分不同导致热膨胀系数不匹配产生了热应力，在界面处出现了水平裂纹和龟裂纹，水平裂纹出现较早且在热应力作用下扩展较快，最终导致喷焊层界面处部分剥落失效。%High-aluminum bronze coating was fabricated on 45# carbon steel substrate by plasma spray welding. The microstructure, phase structure, composition, thermal shock resistance and failure mechanism of the coating were studied. The results show that Fe in the 45# carbon steel substrate diffuses into the coating, the coating combines firmly to the substrate in a metallurgy way. The coating is composed ofα,γ2,β′and k phases, in which k phase is dispersed into the matrix of α, γ2 and β′. Owing to the formation of the eutecoid (α+γ2) be restrained, the toughness is improved. The coating maintains good surface after 33 cycles thermal shock cooled into cold water from heated at 600 ℃. Since the composition and thermal expansion coefficient are different around interface, horizontal cracks and turtle cracks appear in the interface between the coating and sustrate due to thermal stress. Horizontal cracks extend quickly under the action of thermal stress and finally result in the occurrence of large area spallation.
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