Abstract

The modified layer was prepared by adding carbon fiber (C_f) and TiB₂ to 7075 aluminum alloy using friction stir processing (FSP). The metallographic microscope was used to analyze the microstructure of the different regions of the modified layer. The results show that the grain refinement of the modified layer is remarkable and there is an obvious structure of “onion ring” in the modified layer. The closer to the stirring core zone, the higher the grain refinement degree will be. In the core area, the large granular carbon fibers are embedded in the substrate, and the fine granular TiB₂ is distributed around the carbon fibers. Furthermore, there is a clear boundary between the thermo-mechanically affected zone and the heat affected zone, and the boundary has a certain inclination. In the direction of processing depth, the grain refinement is most obvious in the middle layer, and there are obvious metal particles embedded in it.

摘要

通过使用摩擦搅拌处理(FSP)向7075铝合金添加碳纤维(C _f )和TiB ₂来制备改性层。金相显微镜用于分析改性层不同区域的微观结构。结果表明，改性层晶粒细化显着，改性层中存在明显的“洋葱圈”结构。越靠近搅拌核心区，晶粒细化程度越高。在核心区，大颗粒碳纤维嵌入基体，细颗粒TiB ₂分布在碳纤维周围。此外，热力影响区和热影响区之间存在明显的边界，边界具有一定的倾斜度。在加工深度方向，中层晶粒细化最为明显，有明显的金属颗粒嵌入其中。