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摘要为了延长热作模具钢（H13）的使用寿命，本文利用激光熔覆工艺在其表面制备 WC颗粒增强的 Co基合金复合涂层。采用 X 射线衍射仪（XRD）、扫描电镜（SEM）及能谱分析仪（EDS）对涂层的物相组成、显微组织和元素分布情况进行研究，利用显微硬度计和摩擦磨损试验机对涂层的硬度和耐磨性进行测试，并与电弧堆焊的涂层性能进行了对比。实验结果表明：熔覆层由细小致密的树枝晶和等轴晶以及弥散分布的WC颗粒组成，主要包括γ-Co、WC、W2C、CoCx和 Co3W3C 等相。熔覆层的显微硬度高于电弧堆焊层（528HV）且随 WC 含量的增加而逐渐升高。熔覆层的摩擦系数与基底相比大大降低，且低于电弧堆焊工艺表面强化后的摩擦系数（0.3914）；当 WC 含量为 15wt.%时，摩擦系数最小（0.3574）。26050
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毕业论文关键词 激光熔覆 热作模具 钴基复合材料 摩擦磨损
Title Research on WC Particles Reinforced Cobalt Based Alloy Coating
Produced by Laser Cladding and its Performance
Abstract
In this paper, to extend the service life of hot die steel (H13), WC particles
reinforced Co-based alloy composite coating was produced by laser cladding
process. The phase composition, micro-structure, element distribution of the
cladding layer were analyzed in detail through X-ray diffraction (XRD), scanning
electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The
micro-hardness and wear resistance of the cladding layer were tested by Vickers
hardness tester and abrasion testing machine, which was also compared with the
coating produced by arc surfacing.
The experiment results showed that there were fine dendritic crystal and
dispersively distributed WC particles in the cladding layer, The coating mainly
includes γ-Co, WC, W2C, CoCx, Co3W3C phases, and so on. The micro-hardness of the
cladding layer was higher than that of the arc surfacing layer (528HV) and gradually
increased with increase of WC content. Compared with the substrate, the friction
coefficient of the cladding layer reduced greatly, which was lower than that of
the arc surfacing layer (0.3914). When WC content was 15wt.%, the friction
coefficient was the smallest (0.3574).
Keywords laser cladding hot-working die cobalt based composite friction
and wear目 次
1 绪论 1
1.1 模具的失效 1
1.2 激光熔覆在模具表面强化中的应用 1
1.2.1 模具表面强化技术 1
1.2.2 激光表面强化技术 2
1.2.3 激光表面熔覆技术 2
1.3 激光熔覆粉末材料 5
1.3.1 激光熔覆材料 5
1.3.2 WC/Co 基合金复合材料. 6
1.4 本课题的主要研究内容 7
2 实验过程及方法 8
2.1 实验材料 8
2.1.1 基体材料 8
2.1.2 熔覆层粉末材料 8
2.2 实验设备 9
2.2.1 激光快速成形设备 9
2.2.2 其他实验设备 10
2.3 实验流程 10
2.4 实验方法 11
2.4.1 激光熔覆实验 11
2.4.2 熔覆层的组织和物相分析 12
2.4.3 熔覆层的性能分析 13
3 实验结果分析 14
3.1 激光熔覆工艺参数确定 14
3.1.1 激光单道熔覆确定最佳工艺参数 14
3.1.2 激光多道熔覆搭接率确定 15
3.2 激光熔覆层的显微组织研究 16
3.3 激光熔覆层的物相分析 18
3.4 激光熔覆层的显微硬度分析 19
3.5 激光熔覆层的耐磨性分析 21
3.6 激光表面熔覆与电弧堆焊涂层性能比较 25
3.6.1 显微组织和物相 25
3.6.2 显微硬度和摩擦磨损性能 26
结论 28
致谢 29
参考文献 30
1 绪论
1.1 模具的失效
模具制造技术是衡量一个国家现代工业发展水平的标志。进入“十二五”以来，我国模