摘要
利用CO2激光宽带熔覆技术在45钢表面制备了添加纳米WC/Co-N i基、WC/Co-Fe基熔覆层。用SEM、EDS、XRD进行观察和分析,对比研究了添加纳米WC/Co-N i基、WC/Co-Fe基熔覆层的形貌、组织结构、强化相的形状及其分布。结果表明,N i基熔覆层中物相主要为黑色(Fe,N i)、B2Fe3N i3基体上分布着WC、Cr2Fe14C等白色的碳化物相,而Fe基熔覆层中的白色碳化物相中有W2C、Fe3W3C。在优化的工艺参数下,通过连续控制微观结构要素,可以实现成分、组织的变化,获得无气孔、无裂纹的熔覆层。采用EVANS压痕法测得喷焊N i基WC/Co复合陶瓷涂层断裂韧度KIC的平均值为9 MN.m-3/2,而在现有维氏硬度计最大载荷50 kg的情况下,激光熔覆添加纳米WC/Co合金粉末涂层得到的熔覆层仍无裂纹出现,证实了激光熔覆添加纳米WC/Co合金粉末涂层的抗裂作用。
The nano WC/Co-Ni base and nano WC/Co-Fe base composite tungsten carbide coatings were fabricated by wide-band CO2 laser cladding technique on 45 steel.The morphology of laser clad layer was observed by scanning electronic microscope（SEM）,the composition analysis was applied by EDS,and the phase transformation was characterized by XRD.The microstructure,hard phase,and distribution of two types of laser clad coatings were contrastively investigated,including nano WC/Co-Ni base cladding coating and nano WC/Co-Fe base cladding coating.The results indicate that the Ni base cladding coatings are mainly composed of carbides such as WC and Cr2Fe14C which dispersedly distribute in the（Fe,Ni） and B2Fe3Ni3 substrate.But the Fe base cladding coatings are mainly composed of carbides such as W2C and Fe3W3C which dispersedly distribute in the substrate.Under optimized processing parameters,the gradient structure can be realized by sequential controlling micro structural elements.The cladding coating is free of pores and cracks.There into,the average fracture toughness KIC of nanostructured WC/Co-Ni composite coatings prepared by the traditional spray method is 9 MN·m-3/2 measured by EVANS method,but under the Vickers hardness tester in the current maximum load（50 kg）,the WC/Co composite coatings prepared by laser cladding there is no crack,which demonstrates that nanometer phases can serve the anticracking function.
出处
《金属热处理》
CAS
CSCD
北大核心
2011年第6期1-6,共6页
Heat Treatment of Metals
基金
国家自然科学基金面上项目(50772066)
