Phase Field Simulation of AA6XXX Aluminium Alloys Heat Treatment

Abstract

Heat treatment has a significant impact on the microstructure and the mechanical properties of Al-Mg-Si alloys. The present study presents a first Phase-Field modelling approach on the recrystallisation and grain growth mechanism during annealing. It focuses on the precipitate fraction, radius, and Mg-Si concentration in the matrix phase, which are used as input data for the calculation of the yield strength and hardness at the end of different ageing treatments. Annealing and artificial ageing simulations have been conducted on the MultiPhase-Field based MICRESS@ software, while the ThermoCalc@ software has been used to construct the pseudo-binary Al-Mg phase-diagrams and the atomic-mobility databases of MgxSiy precipitates. Recrystallisation simulation estimates the recrystallisation kinetics, the grain growth, and the interface mobility with the presence/absence of secondary particles, selecting as annealing temperature 400 °C and a microstructure previously subjected to cold rolling. The pinning force of secondary particles decelerates the overall recrystallisation time, causing a slight decrease in the final grain radius due to the reduction of interface mobility. The ageing simulation examines different ageing temperatures (180 and 200 °C) for two distinct ternary systems (Al-0.9Mg-0.6Si/Al-1.0Mg-1.1Si wt.%) considering the interface energy and the chemical free energy as the driving force for precipitation. The combination of Phase-Field and the Deschamps–Brechet model predicted the under-ageing condition for the 180 °C ageing treatment and the peak-ageing condition for the 200 °C ageing treatment.

Structure–Properties–Processing Relationships in Metallic Materials

“…Baganis et al [3] apply phase field simulation for the optimization of Al6XXX heat treatment in order to help understand how microstructure evolution during heat treatment, more specifically recrystallisation kinetics, grain growth and interface mobility, affects the mechanical properties of this Al-Mg-Si alloy family. their work, Guo et al [4] show the important role of trace impurities such as phosphorus and rare earth cerium on the hot ductility in the performance of advanced SA508-4N RPV steel. The addition of P and Ce is able to facilitate the occurrence of the dynamic recrystallization (DR) of the steel, lowering the initial temperature of DR from ~900 to ~850 • C and thereby enhancing the hot ductility performance.…”

“…The addition of P and Ce is able to facilitate the occurrence of the dynamic recrystallization (DR) of the steel, lowering the initial temperature of DR from ~900 to ~850 • C and thereby enhancing the hot ductility performance. Consequently, the combined addition of P and Ce can significantly improve the hot ductility of SA508-4N RPV steel, thereby improving its continuous casting performance and hot workability [4].…”

Microstructural Evolution in a 6060 Extrudable Al-Alloy: Integrated Modeling and Experimental Validation

“…A multiscale model based on Density Functional Theory (DFT), Monte-Carlo (MC) and phase-field approaches was developed by Kleiven and Akola [22], aiming at investigating the formation of Mg-Si rich precipitates in the FCC matrix of Al-Mg-Si alloys, showing that the precipitates tend to form elongated domains either by Ostwald ripening or by coalescence, as precursors to the needle-like β ′′ precipitates. Finally, Baganis et al [23] presented a phase field simulation of precipitation in 6061 and 6082 alloys predicting under-aging and peak-aging conditions for different aging temperatures.…”

Energy Dissipation Enhancement of Thin-Walled 6063 T5 Aluminium Tubes by Combining a Triggering Mechanism and Heat Treatment

“…For aluminium, due to its alloying materials, the heat treatment can involve artificial ageing, which consists of heating the tube in a furnace for a specific time, allowing oversaturated phases formed during manufacturing to precipitate. These precipitated phases increase mechanical strength by blocking dislocations [25].…”