Novel Al-Mg-Si-Cu-Mn Alloy Design Based on Phase Diagram Calculations

Author of the article:GAO Chenqi, TIAN Lusha, LI Jianping

Author's Workplace：School of Materials and Chemical Engineering, Xi'an Technological University, Xi'an 710021, China

Key Words：phase diagram calculation; aluminium alloy; mechanical properties; microstructure

Abstract：On the basis of thermodynamic calculations of phase diagrams, the phase composition of a new type ofAl-Mg-Si-Cu-Mn alloy was calculated under different Mg contents and Mg/Si mass ratios, and the mechanical properties ofthe alloy in the as-cast state were simulated. Two aluminium alloys with compositions of Al-1.5Mg-1.1Si-0.8Cu-0.2Mn andAl-1.0Mg-1.0Si-0.8Cu-0.2Mn were obtained. The microstructures and mechanical properties of the two alloys with differentcompositions were observed and tested via optical metallographic microscopy, scanning electron microscopy and roomtemperature tensile tests. The results show that with increasing Mg content and Mg/Si mass ratio, the average grain size ofthe as-cast Al-1.5Mg-1.1Si-0.8Cu-0.2Mn alloy is reduced by 30% compared with that of the as-cast Al-1.0Mg-1.0Si-0.8Cu0.2Mn alloy; the maximum tensile strength of the as-cast Al-1.5Mg-1.1Si-0.8Cu-0.2Mn alloy reaches 177 MPa, which is12.5% greater on average than that of the as-cast Al-1.0Mg-1.0Si-0.8Cu-0.2Mn alloy. Overall, the mechanical propertiesand microstructure of the as-cast Al-1.5Mg-1.1Si-0.8Cu-0.2Mn alloy were optimized and improved to a certain extent.Moreover, the simulation results are consistent with the experimental results, which indicates that the phase diagramthermodynamic calculation software JMatPro is beneficial for improving the efficiency of alloy composition design.