盛永琦,危亚城,尚大智,夏琨,申屠成望,冯爱新.激光熔覆Ni/WC梯度复合涂层的组织与性能研究[J].表面技术,2024,53(15):152-162.
SHENG Yongqi,WEI Yacheng,SHANG Dazhi,XIA Kun,SHENTU Chengwang,FENG Aixin.Microstructure and Properties of Laser Cladded Ni/WC Gradient Composite Coatings[J].Surface Technology,2024,53(15):152-162 |
| 激光熔覆Ni/WC梯度复合涂层的组织与性能研究 |
| Microstructure and Properties of Laser Cladded Ni/WC Gradient Composite Coatings |
| 投稿时间：2023-07-15 修订日期：2023-11-10 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.15.014 |
| 中文关键词: 激光熔覆 Ni/WC 梯度复合涂层 硬度 耐磨性 冲击韧性 |
| 英文关键词:laser cladding Ni/WC gradient composite coating hardness wear resistance impact toughness |
| 基金项目:温州市科技局重大科学与科技专项(2018ZG018);温州大学瑞安研究生院科创课题(YC202212006) |
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| Author | Institution |
| SHENG Yongqi | College of Mechanical and Electrical Engineering,Rui'an Graduate College, Wenzhou University, Zhejiang Wenzhou 325035, China |
| WEI Yacheng | College of Mechanical and Electrical Engineering,Rui'an Graduate College, Wenzhou University, Zhejiang Wenzhou 325035, China |
| SHANG Dazhi | College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China |
| XIA Kun | College of Mechanical and Electrical Engineering,Rui'an Graduate College, Wenzhou University, Zhejiang Wenzhou 325035, China |
| SHENTU Chengwang | College of Mechanical and Electrical Engineering,Rui'an Graduate College, Wenzhou University, Zhejiang Wenzhou 325035, China |
| FENG Aixin | College of Mechanical and Electrical Engineering,Rui'an Graduate College, Wenzhou University, Zhejiang Wenzhou 325035, China;Zhejiang Provincial Key Laboratory of Laser Processing Robots/Key Laboratory of Laser Processing and Testing in Machinery Industry, Zhejiang Wenzhou 325035, China |
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| 中文摘要: |
| 目的 减少涂层内部缺陷，提高Cr12MoV模具钢表面的显微硬度及耐磨性。方法 采用激光熔覆技术在Cr12MoV钢上逐层制备Ni60-Ni60/25%WC(Ni/WC)梯度复合涂层。借助X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)、显微硬度计、摩擦试验机和冲击试验机，研究梯度复合涂层的物相组成、微观组织、显微硬度、耐磨性与冲击韧性。结果 在Cr12MoV的基体上制备Ni/WC梯度复合涂层，Ni60层与Ni60/25%WC冶金结合理想。Ni/WC梯度复合涂层的表面主要物相为γ-(Fe, Ni)、FeNi3、CrB、Cr7C3、Cr23C6，从Ni60层底部到顶部依次为胞状晶、柱状晶、细小的等轴枝晶。Ni/WC梯度复合涂层硬度呈梯度分布，涂层的平均硬度达到698.5HV，相较于基体提高了约55.2%。与基体相比，Ni/WC梯度复合涂层表现出更好的耐磨性能，摩擦系数和磨损率分别下降了40.92%和28.6%，其中基体表现为黏着磨损，然而涂层整体表现为磨粒磨损。但较基体而言，Ni/WC梯度复合涂层的冲击韧性值降低了32.48%，复合涂层区域表现为脆性断裂。结论 Ni/WC梯度复合涂层冶金结合良好，同时与基体相比，Ni/WC梯度复合涂层可以有效提高硬度及耐磨性，但冲击韧性有所降低。 |
| 英文摘要: |
| Cr12MoV is commonly used in molds for automotive seat frames. In practical applications, mold steel is subject to high impact forces and friction, ultimately leading to failure and affecting the service life of the mold. Laser cladding technology is currently an advanced surface repair technique. In order to improve the microhardness and wear resistance of the surface of Cr12MoV die steel and reduce the internal defects of the coating, in this paper, laser cladding technology was adopted to sequentially prepare Ni60-Ni60/25%WC (Ni/WC) gradient composite coatings on the surface of Cr12MoV steel. An X-ray diffractometer (XRD) was used to analyze the phase composition of the coating, a scanning electron microscope (SEM) was used to characterize the microstructure, an energy dispersive spectrometer (EDS) was used to analyze the element distribution of the coating, and a three-dimensional profilometer was used to observe the wear morphology. The hardness, wear resistance, and impact toughness of the gradient composite coating were tested with a microhardness tester, a friction and wear testing machine, and an impact testing machine, respectively. The research indicated that the Ni60 layer and the Ni60/25%WC layer achieved ideal metallurgical bonding when preparing Ni/WC gradient composite coatings on the substrate of Cr12MoV. The main phases on the surface of the Ni/WC gradient composite coating were γ-(Fe, Ni), FeNi3, CrB, Cr7C3, and Cr23C6. From the bottom to the top of the Ni60 layer, the microstructure transited from cellular crystals to columnar crystals, and finally to fine equiaxed dendrites. And from the performance point of view, the Ni/WC gradient composite coating exhibited a gradient distribution of hardness, which decreased with increasing depth. This was mainly due to the re-diffusion of alloying elements in the sub-surface layer after multiple cladding processes, resulting in a more uniformly distributed strengthening phase throughout the gradient coating. The average hardness of the coating reached 698.5HV, which was a 55.2% improvement compared with the substrate. Compared with the substrate, the Ni/WC gradient composite coating exhibited excellent wear resistance. The friction coefficient and wear rate were reduced by 40.92% and 28.6%, respectively. While the substrate showed adhesive wear, the coating as a whole demonstrated abrasive wear. This behavior was closely related to the increased hardness of the coating. The improved hardness of the Ni/WC gradient composite coating allowed it to resist wear caused by abrasive particles. The harder coating could effectively withstand the forces and interactions between the coating and abrasive particles, reducing the friction coefficient and wear rate. The presence of the gradient distribution in hardness further enhanced its resistance to wear, as different regions of the coating possess varying levels of hardness that contributed to its overall wear performance. However, compared with the substrate, the Ni/WC gradient composite coating exhibited a decrease of 32.48% in impact toughness value and showed brittle fracture behavior. Due to the presence of reinforcing phases in the coating, the material was more prone to crack propagation, while the lower impact toughness value limited its ability to absorb energy and inhibited crack propagation. This resulted in an increased likelihood of fracture occurring in the coating when it was subject to impact. In summary, the Ni/WC gradient composite coating exhibits good metallurgical bonding compared with the substrate. It effectively improves hardness and wear resistance. However, there is a slight decrease in impact toughness. |
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