Characteristics of machined surface integrity in face milling Al-Li alloy 2A97 with carbide inserts

2A97 is one of the latest generations of Al-Li alloys that can be widely applied in the aerospace field which always takes weight reduction into consideration. An experimental investigation was conducted to study the machined surface integrity characteristics in face milling 2A97 with cemented carbide inserts on the basis of Taguchi orthogonal method. The multi-surfaces of chips and the rake faces of inserts were characterized. The effects of cutting process parameters, namely the cutting speed, the feed rate per tooth, the depth and width of cut on the machined surface roughness and residual stresses, were found out through range analysis. The work hardening and microstructure of machined surface layer were analyzed. The research results revealed that severe plastic deformation was developed during the chip formation process. Micro-chippings that situated along cutting edges constituted worn morphology of carbide inserts. The feed rate per tooth fz and depth of cut ap were more important than the width of cut ae and cutting speed vc to the machined surface roughness. Work hardening with different levels and residual stresses with small magnitudes were found on these machined surfaces. Little change was observed in the cross-sectional microstructure. In general, the similar machined surface integrity characteristics were observed in face milling 2A97 and conventional aluminum alloys. This conclusion can provide the foundation for applying widely 2A97 in aerospace industry.