Investigating the Influence of Mg Content Variations on Microstructures, Heat-Treatment, and Mechanical Properties of Al-Cu-Mg Alloys

• Published in: Materials 2023-06, Vol.16 (12), p.4384
• Main Authors: Shah, Abdul Wahid, Ha, Seong-Ho, Siddique, Jabir Ali, Kim, Bong-Hwan, Yoon, Young-Ok, Lim, Hyun-Kyu, Kim, Shae K
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum; Aluminum base alloys; Aluminum industry; Copper; Crystal structure; Ductility; Elongation; Heat treatment; Intermetallic compounds; Investigations; Magnesium; Mechanical properties; Microstructure; Phase diagrams; Phases; Precipitates; Precipitation hardening; Scanning electron microscopy; Software; Solidification; Specialty metals industry; Spectrum analysis; Temperature; Tensile properties; Tensile strength; Titanium base alloys; Transportation equipment industry; Yield strength
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16124384

The objective of this study was to examine the impact of varying magnesium levels in the α-Al + S + T region of the Al-Cu-Mg ternary phase diagram on the solidification process, microstructure development, tensile properties, and precipitation hardening of Al-Cu-Mg-Ti alloys. The outcomes indicate that alloys with 3% and 5% Mg solidified with the formation of binary eutectic α-Al-Al CuMg (S) phases, whereas in the alloy with 7% Mg, the solidification process ended with the formation of eutectic α-Al-Mg (Al, Cu) (T) phases. Additionally, a significant number of T precipitates were noticed inside the granular α-Al grains in all alloys. In the as-cast condition, the 5% Mg-added alloy showed the best combination of yield strength (153 MPa) and elongation (2.5%). Upon T6 heat treatment, both tensile strength and elongation increased. The 7% Mg-added alloy had the best results, with a yield strength of 193 MPa and an elongation of 3.4%. DSC analysis revealed that the increased tensile strength observed after the aging treatment was associated with the formation of solute clusters and S″/S' phases.