激光熔敷金属陶瓷涂层工艺研究
毕业论文关键字：WC 熔敷层；裂纹；硬度；摩擦磨损；显微组织
Abstract Since the rapid development of laser technology in the middle of twentieth Century, laser cladding is a new surface modification technology. Laser cladding is not only suitable for wide application, saving a large amount of precious metal resources, but also easy to realize automatic production. In this paper, a layer of WC coating was deposited on the surface of 16Mn steel by laser cladding, and the influence of different scanning speeds on the surface forming of the cladding layer was studied. By using SEM and EDS ,we observe the microstructure changes of deposited area. The hardness variation of different scanning speed was measured and compared with the micro hardness tester. The friction and wear properties of WC melt layer at high temperature were analyzed. Through the experiment, it is found that the hardness of cladding layer can be improved obviously by the appropriate scanning speed, which can be improved by five times. When the scanning speed is 3mm/s, the laser irradiation time is long, and it is easy to cause the grain coarsening. The scanning speed of 5mm/s may result in the presence of melt powder particles in the cladding layer. The wear resistance of cladding layer has been improved, mainly because of the support and protection of WC particles on the surface. The appearance of the oxide film is also beneficial to the wear performance. Through research and analysis, it is found that the formation of cracks is mainly due to the combined effects of thermal stress, tissue stress and residual stress.
Key words: WC cladding; crack; hardness; friction and wear; microstructure
目录
第一章绪论1
1.1引言..1
1.2激光熔敷技术1
1.2.1激光熔敷的特点...2
1.2.2激光熔敷的应用...3
1.3本课题的研究现状..4
1.4本次课题的研究目的、内容与意义....5
1.4.1研究目的5
1.4.2本次课题的主要研究内容..5
1.4.3研究意义6
1.5激光熔敷研究中存在的问题与研究展望.6
1.5.1涂层剥落与烧损的问题.6
1.5.2涂层开裂的问题...7
1.5.3激光工艺参数选择的问题..7
1.5.4激光熔敷研究展望....7
第二章实验准备及实验方法9
2.1实验材料...9
2.1.1基体实验材料..9
2.1.2熔敷粉末材料..9
2.2实验设备.10
2.2.1激光器..10
2.2.2送粉器..11
2.3实验方案的设计....12
2.4试验分析方法...12
2.4.1试样的切割与镶嵌..12
2.4.2金相磨样与分析.13
2.4.3显微硬度测试14
2.4.4摩擦磨损性能测试..15
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