摘要
采用聚焦光束热源在 45钢母材上获得了镍基合金粉末堆焊层 ,研究了堆焊层的物相组成及母材热影响区的微观组织特征。X射线衍射、SEM、EDS及显微硬度分析结果表明 ,Ni35堆焊层的显微组织由少量共晶基底上分布着大量初生的γ Ni枝晶组成。基底的绝大部分为M2 3 (C ,B) 6+γ Ni网状共晶 ,局部区域析出了γ Ni+Ni3 Si层片状共晶。母材表面半熔化区的形成使堆焊层与基材实现了熔化冶金结合 ,堆焊层金属逆热流方向与母材呈联生方式长大。母材热影响区的奥氏体在冷却过程中转变为类珠光体组织 ,随热影响区离熔合线距离的增加 。
The Ni based alloy powder surfacing layer was obtained by light beam surfacing on the 45 steel and the microstructure of heat affected zone(HAZ) and the phase of the surfacing layer were studied.The results of X ray diffraction?SEM?EDS and microhardness test show that the microstructure of Ni35 powder surfacing layer is composite of a little eutectic and mass of primary γ Ni dendrite among the eutectic.Most of the eutectic is reticulated M 23 (C,B) 6+γ Ni and a little lathlike Ni 3Si+γ Ni eutectic is precipitated in some region.There is metallurgical bonding between the base metal and the layer owing to the formation of the partially melted zone in the substrate metal.Grains in the melted pool tend to epitaxially grow in the direction opposite to the thermal flow.The microstructure of HAZ is perlite like transformed from austenite and the amount of ferrite precipitation in the grain boundary increases as the distance increasing between the fusion boundary and the HAZ.
出处
《金属热处理》
CAS
CSCD
北大核心
2002年第2期1-3,共3页
Heat Treatment of Metals
基金
国家自然科学基金项目 (5990 50 1 7)
并得到清华大学 985基金和实验室开放基金资助
