Horizontally Solidified Al-3 wt％Cu-(0.5 wt％Mg) Alloys: Tailoring Thermal Parameters, Microstructure, Microhardness, and Corrosion Behavior

• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2019,（6）
• 页码范围: 695-709
• 页数: 15页
• 语种: 英文

摘要

In the present experimental investigation,Al-3 wt％Cu and A1-3 wt％Cu-0.5 wt％Mg alloys castings are produced by a horizontal solidification technique with a view to examining the interrelationship among growth rate (GR),cooling rate (CR),secondary dendrite arm spacing (λ2),Vickers microhardness (HV),and corrosion behavior in a 0.5 M NaC1 solution.The intermetallic phases of the as-solidified microstructures,that is,θ-Al2Cu,S-A12CuMg,and ω-Al7Cu2Fe,are subjected to a comprehensive characterization by using calculations provided by computational thermodynamics software,optical microscopy,and scanning electron microscopy/energy-dispersive spectroscopy.Moreover,electrochemical impedance spectroscopy and potentiodynamic polarization tests have been applied to analyze the corrosion performance of samples of both alloys castings.Hall-Petch-type equations are proposed to represent the HV dependence on λ2.It is shown that the addition of Mg to the Al-Cu alloy has led to a considerable increase in HV;however,the A1-Cu binary alloy is shown to have lower corrosion current density (icorr) as well as higher polarization resistance as compared to the corresponding results of the A1-Cu-Mg ternary alloy.