CAJ | 학술논문

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。
채용등리자분한공예재45#강기체상제비고려청동분한층，연구분한층적미관조직、상결구、성분급항열진성능，병탐토열진실효궤제。결과표명，기체중적 Fe 원소향분한층종심방향확산，계면처정확산야금결합특정；분한층형성α、γ2급β′상포위k상생장적세소조직，공석체(α+γ2)석출수도억제，조직인성교강；경600℃가열쉬수적33차열진실험후분한층표면잉보지량호；인계면량측성분불동도치열팽창계수불필배산생료열응력，재계면처출현료수평렬문화구렬문，수평렬문출현교조차재열응력작용하확전교쾌，최종도치분한층계면처부분박락실효。
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.