Microstructural Evolution and Mechanical Properties of a Continuously Cast Al-Mg-Si-Cu Alloy Processed by Repetitive Continuous Extrusion Forming

A continuously cast Al-Mg-Si-Cu alloy was processed by repetitive continuous extrusion forming (R-Conform) and the corresponding deformation behaviors, microstructural evolution and mechanical properties were investigated systematically by combining uniaxial compression deformation, finite element simulation, microstructural observation and mechanical test. The results showed that the grain size of Al-Mg-Si-Cu alloy bar was gradually refined and became more uniform after R-Conform processing with the increase of pass as a result of continuous dynamic recrystallization. The evolution of microstructure was related to the complex thermomechanical conditions of temperature, shear rate and the distribution of accumulated strain during R-Conform process. Then the improvement of properties was obtained by the refined grains after R-Conform processing. Further, the dense and fine precipitates formed after solution treatment and aging led to optimized mechanical properties with tensile strength approximate 400 MPa and elongation about 17.8%.

Automated summary

A continuously cast Al-Mg-Si-Cu alloy was processed by repetitive continuous extrusion forming (R-Conform) to refine the grain size and improve the mechanical properties. The microstructural evolution and mechanical behavior were studied through uniaxial compression deformation, finite element simulation, microstructural observation, and mechanical test. The results showed that continuous dynamic recrystallization occurred during the R-Conform process, leading to gradually refined and more uniform grain size. Solution treatment and aging further improved the mechanical properties with a tensile strength of approximately 400 MPa and an elongation of about 17.8%.