FGH96合金惯性摩擦焊焊区的微观组织表征-中国材料进展

文章信息/Info

Title:: Microstructure Characterization of Inertia Friction Bonding Region for NickelBased Superalloy FGH96

Author(s):: WANG Xiaofeng; ZOU Jinwen; YANG Jie; LIU Guangxu; XU Zhexin; (Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China)

Keywords:: powder metallurgy nickelbased superalloy; inertial friction bonding; microstructure; heat treatment after welding

摘要:: 研究了FGH96镍基粉末高温合金的惯性摩擦焊微观组织。惯性摩擦焊在焊缝（WL）区形成非常陡峭的温度梯度，整个焊接过程发生在几秒以内，是快速加热和快速冷却过程，焊区发生了完全再结晶，焊缝区组织与基体组织有显著差异。在焊缝上分布有尺寸均匀的高密度细小γ′相，快速冷却得到的细小γ′相呈球形，随着轴向与焊缝的距离变大，球形γ′相逐渐转变为立方体形貌。同时由于存在再结晶过程，在焊缝大变形区域未发现有明显的变形晶粒。相比于标准焊后热处理，高温焊后热处理工艺能显著减小焊缝细晶区域的宽度，并能将焊缝处的二次γ′相体积分数从标准热处理的0%提高到25%以上，这为高效调控惯性摩擦焊构件的微观组织提供了实验依据。

Abstract:: The microstructure of inertia friction welding P/M ., a fast heating and cooling process with recrystallization occurring in the welding area. A dramatic change of the microstructure was observed over a narrow welding zone. A significant change of the γ′ distribution was observed across the welding line with very fine γ′ particles precipitated in unimodal size distribution. The fine precipitated γ′ under fast cooling was spherical in shape, which gradually transformed into elliptical, cube shape as the distance from welding line increased. No significant grain distortion was observed in the extensively plastically deformed region due to recrystallization. Compared with the standard post-weld heat treatment, heat treatment with higher temperature could significantly reduce the width of the fine grain area at the welding zone. The volume fraction of the weld line secondary γ′ phase increased from 0% to ~25% when higher temperature heat treatment was applied. Those findings are essential for controlling the microstructure of inertial friction welding component on P/M superalloys.