摘要
利用6 kW光纤激光器在Q235钢表面激光熔覆Ni基WC复合涂层。使用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)、显微硬度计和磨损试验机,研究了不同WC颗粒含量下熔覆层组织形态、成分、显微硬度和磨损性能的变化规律。结果表明:熔覆层的稀释率随着WC含量的增加先减小后增加,当WC含量为20%时,稀释率最小。在光纤激光熔覆Ni基WC复合涂层的过程中,WC颗粒部分发生溶解并与其他元素相互作用形成共晶物,析出后分别以条状、块状和粒状等形态存在,随着WC含量的增加,熔覆层的组织出现细化现象。含WC的熔覆层组织中主要有γ-Ni、M_7C_3、M_(23)C_6、CrB、WC和W_2C等相存在。随着WC含量增加,熔覆层硬度增加,当WC质量分数达到40%时,熔覆层硬度可达到基体硬度的5倍以上。当WC的相对质量分数为20%时,熔覆层耐磨性能最好,耐磨性为Ni60A涂层的3倍以上。
Laser clad Ni-based WC composite coating was fabricated on Q235 steel surface by using a 6 kW fiber laser. The morphology, composition, microhardness and wear resistance of the composite coating with different content of WC particles were studied by means of scanning electron microscopy （SEM） , energy dispersive spectroscopy （EDS） , X-ray diffraction （XRD）, microhardness and wear tests. The results show that with the increasing of content of WC particles, the dilution rate of the cladding layer decreases firat and then increases, when the WC content is 20% , the dilution rate is minimum. In the process of fiber laser cladding the mixture of WC particles and Ni-based alloy powder, residual WC particles partially dissolve and react with other elements to form eutectics, which exist with the shape of lumpy, strip and spherical. With the increasing of WC content, the structure of the cladding layer is refined. The main phases of the laser cladding layer are γ-Ni, M7C3, M23 C6, CrB, WC and W2C. With the increasing of WC content, the average hardness of the cladding layers increases ; when the mass percent of WC particles is 40% , the average hardness of the composite coating can reach more than five times of the matrix. When the mass percent of WC particles is 20% , wear resistance of the cladding layer is the best, the wear resistance of the coating can reach more than three times of the Ni60A coating.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2016年第7期172-179,共8页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51275006
51274016)
北京市自然科学基金(2142009)
