Metal Flow Characteristics and Deformation Analyses in Hot Extrusion of 6063, 5052 and 5083 Al-Alloys

摘要

Detailed analyses of the metal flow characteristics of Al-Mg-Si alloy (6063) and Al-Mg alloys (5052 and 5083) were carried out in a series of plane strain hot extrusion experiments. Symmetric flat dies with a 90 deg. die angle and nonsymmetric wedge dies with 90 deg. and 15 deg. die angles were employed to investigate dead metal zone formation and friction conditions in the hot extrusion process. Distributions of flow velocity, effective strain rate and effective strain in the deformation zone in steady state extrusion were also analyzed quantitatively. Flow curves and extrusion curves of 5052 and 5083 alloys have a higher load level than those of 6063 alloy. The shearing plane along the dead metal zone is steeper in extrusion of 5052 and 5083 alloys than in that of 6063 alloy. A dead metal zone is formed in 5052 and 5083 alloys on both the 90 and 15 deg. die angle sides, while a dead metal zone is formed in 6063 alloy on only the 90 deg. die angle side. The flow curves of 5083 alloy show work-softening due to dynamic recrystallization at the hot extrusion temperature. Therefore, the velocity distribution pattern of 5083 alloy is different from those of 6063 and 5052 alloys.