Evolution of the Material Microstructures and Mechanical Properties of AA1100 Aluminum Alloy within a Complex Porthole Die during Extrusion.

Ding Tang,Dayong Li,Yinghong Peng,Huamiao Wang,Peidong Wu,Wenli Fang,Zihan Li,Xiaohui Fan,Tianxia Zou

doi:10.3390/ma12010016

Ding Tang, Dayong Li + Show 7 more

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https://doi.org/10.3390/ma12010016

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Abstract

Microchannel tube (MCT) is widely employed in industry due to its excellent efficiency in heat transfer. An MCT is commonly produced through extrusion within a porthole die, where severe plastic deformation is inevitably involved. Moreover, the plastic deformation, which dramatically affects the final property of the MCT, varies significantly from location to location. In order to understand the development of the microstructure and its effect on the final property of the MCT, the viscoplastic self-consistent (VPSC) model, together with the finite element analysis and the flow line model, is employed in the current study. The flow line model is used to reproduce the local velocity gradient within the complex porthole die, while VPSC model is employed to predict the evolution of the microstructure accordingly. In addition, electron backscatter diffraction (EBSD) measurement and mechanical tests are used to characterize the evolution of the microstructure and the property of the MCT. The simulation results agree well with the corresponding experimental ones. The influence of the material’s flow line on the evolution of the orientation and morphology of the grains, and the property of the produced MCT are discussed in detail.

Highlights

Multi-port extrusion (MPE) tubes are widely applied in industry to transfer the substances of liquid, gas or slurries etc
Three flow lines are extracted from the velocity field at locations close to the bridge, close to the top surface of the die, and in between
We found that the flow lines extracted from the finite element (FE) analysis can be well described by 4 sectioned polynomial functions with maximum degree of 4

Summary

Introduction

Multi-port extrusion (MPE) tubes are widely applied in industry to transfer the substances of liquid, gas or slurries etc. An MCT is commonly produced through a processing chain of extrusion, rolling and brazing [1,2,3,4]. The extrusion process, which involves severe plastic deformation, affects the final microstructure the most, though both rolling and brazing are important as well. The microstructure of aluminum alloys under thermal-mechanical loading have been extensively investigated [1,2,3,4,5,6], which eventually governs the mechanical properties of the MCTs. the MCT is produced by the porthole extrusion die with the specially designed mandrel [7]. The large extrusion ratio and the existence of the mandrel lead to assorted flow and severe deformation of the base material, and complicated evolution of the microstructure. The features of the microstructure developed under extrusion are Materials 2019, 12, 16; doi:10.3390/ma12010016 www.mdpi.com/journal/materials

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