聚焦光束表面合金化机理和工艺的研究  

Mechanism and Process of Light Beam Surface Alloying

作　　者：单际国[1] 张迪[1] 余顺周[1] 任家烈[1] 

机构地区：[1]清华大学机械工程系,北京100084

出　　处：《材料热处理学报》2001年第3期37-40,共4页Transactions of Materials and Heat Treatment

基　　金：国家留学回国人员启动基金;清华大学机械工程院 985基础研究基金资助

摘　　要：采用SEM、X射线、光学显微镜、显微硬度计等手段研究了高能密度光束表面合金化的机理和工艺。用NiCrBSi合金粉末对灰口铸铁表面实现光束合金化的实验研究表明 ,光束线能量及合金粉末用量是表面合金化区合金化程度的重要决定因素。合金化程度低的合金化层微观组织具有亚共晶特征 ,莱氏体中的碳化物为Fe3C ,部分γ Fe转变为马氏体。合金化程度高的合金化层微观组织为γ - (Fe ,Ni)奥氏体基底上弥散分布的Fe2 3(CB) 6 球状碳化物。碳化物形态的改变及常温奥氏体量的增加使合金化层表面硬度降低 ,但有利于韧性和耐腐蚀性能的改善。In this paper the mechanism and process of light beam surface alloying were investigated by SEM, X-ray diffraction, optical microscope, microhardness etc. The NiCrBSi powder alloying on the surface of grey cast iron was realized successfully by means of light beam heating. The results show that the light beam heat input and the amount of alloy powder are the important factors which can determine the degree of alloying of surface alloying zone. The microstructure of the layer with low alloying degree has the hypoeutectic character, of which the carbide in ledeburite is Fe 3C and part of γ-Fe transforms into α-Fe (martensite). The microstructure of the layer with high alloying degree is γ-(Fe, Ni) austenite matrix at room temperature with dispersed Fe 23 (C, B) 6 spherulitic carbide. The change of precipitation morphology of carbide and the increase of austenite at room temperature, resulting from the heightening of alloying degree, decrease surface hardness of alloying layer, which can improve the toughness and the anticorrosion of alloying layer.

关 键 词：聚焦光束 表面合金化 灰口铸铁 

分 类 号：TG174.445+3[金属学及工艺—金属表面处理]