激光熔覆MoSi_2复合涂层组织演变与性能研究  

Microstructure and Properties of Laser Cladding MoSi_2 Composite Coating

作　　者：杨胶溪[1] 王志成[1] 王欣[1] 胡星[1] 

机构地区：[1]北京工业大学激光工程研究院,北京100124

出　　处：《中国激光》2013年第12期58-64,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(50971004);国家973计划(2011CB606305-3)

摘　　要：使用光斑直径为3mm的CO2激光器制备单一MoSi2熔覆层,通过X射线衍射仪(XRD)和扫描电镜(SEM)检测得出熔覆层内部长条枝晶主要为(Fe,Si)2Mo,枝晶间主要为α-Fe、Fe2Si两相共晶,涂层显微硬度在700HV左右。通过积分镜变换改进光斑得到尺寸为6mm×2mm的宽带矩形光斑,再进行Ni/MoSi2混合粉末的激光熔覆,发现随着Ni基合金量的增加,裂纹率明显降低,得到Ni、MoSi2临界质量比为3:7,并通过热应力和稀释率计算证明宽带激光熔覆能够适当地减小热拉应力的产生,并在一定程度上降低稀释率。最后通过XRD,能谱仪(EDS)等检测得出Ni/MoSi2样品中高Mo枝晶主要为MoSi2相和NiMo相,高Mo含量枝晶处显微硬度为整个涂层最大值,达到861.9HV,涂层显微硬度在750HV左右,大大地改善了基体的相关性能。Single MoSi2 cladding is prepared by C02 laser with a spot diameter of about 3 ram. The main phase of long dendrite in the cladding layer is （Fe, Si）2 Mo, as revealed by X-ray diffraction （XRD） and scanning electron microscope （SEM） detection. The interdendritic phase is mainly a-Fe and Fe2Si. Micro-hardness of the coating is maintained at about 700 HV. The spot is shaped to a rectangle with the size of 2 mmX 6 ram, and the cladding of Ni/MoSi2 mixed powder is then performed. It is found that as the Ni-based alloy increases, the cracks are significantly reduced, and the critical mass ratio of Ni and MoSi2 is 3：7. By calculating thermal stress and dilution ratio, it is proved that broadband laser cladding can be appropriate to reduce the thermal tensile stress and dilution rate. Finally, XRD and energy dispersive spectrometry （EDS） are used to detect the Ni/MoSi2 cladding and the main phases of high Mo dendrite are found to be MoSi2 and NiMo. The average micro-hardness is 750 HV and the maximum microhardness is 861.9 HV, present in the dendrite of coating, achieving the purpose of improving substrate physical properties.

关 键 词：激光技术 激光熔覆 宽带光斑 (Fe Si)2Mo相 显微硬度 

分 类 号：TG174.44[金属学及工艺—金属表面处理]