论文部分内容阅读
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 ,铁素体在晶界析出量增加
The nickel-base alloy powder surfacing layer was obtained on a 45 steel base material by using a focused beam heat source. The phase composition of the surfacing layer and the microstructure of the HAZ were studied. The results of XRD, SEM, EDS and microhardness analysis show that the microstructure of Ni35 surfacing layer consists of a large number of primary γ Ni dendrites distributed on a few eutectic substrates. The vast majority of the substrates are M2 3 (C, B) 6 + γ Ni reticular eutectic, and the localized regions are exfoliated with γ Ni + Ni3 Si lamellar eutectic. The formation of semi-molten zone on the surface of the base metal resulted in the fusion metallurgical bonding between the overlay and the substrate. The direction of the overheated metal in the overlay layer grew up with the base metal in a symbiotic way. During the cooling process, the austenite in the heat affected zone (HAZ) of the base material changes into pearlite-like structure. With the increase of the distance from the weld line in the heat affected zone, the amount of precipitation of ferrite in the grain boundary increases