Microstructural Evolution and Mechanical Properties of AE45-Gd Magnesium Alloy Under Different Aging Processes

Area of Science:

• Materials Science
• Metallurgy
• Mechanical Engineering

Background:

• Magnesium alloys, particularly AE45-Gd, are crucial for lightweight structural applications.
• Understanding microstructural evolution during aging is key to optimizing mechanical properties.
• The presence of multi-scale second phases (Al2RE and Al11RE3) influences alloy performance.

Purpose of the Study:

• To investigate the impact of artificial aging and aging under pressure on AE45-Gd magnesium alloy.
• To analyze microstructural evolution, age-hardening behavior, and mechanical property changes.
• To determine optimal aging parameters for improved material performance.

Main Methods:

• Preparation of as-extruded AE45-Gd magnesium alloy.
• Application of conventional isothermal aging and aging under pressure.
• Microstructural analysis (including Ostwald ripening observation) and mechanical property testing (yield strength, tensile strength, elongation).

Main Results:

• Conventional aging improves mechanical properties; higher temperatures slightly decrease peak hardness but shorten aging time.
• Aging under pressure significantly reduces aging time with minimal impact on peak hardness.
• Optimal aging at 200°C for 16h yields a yield strength of 183.95 MPa, tensile strength of 322.50 MPa, and elongation of 4.32%.
• Microcracking initiates at coarse Al2RE compounds, while fine Al11RE3 particles show less cracking, with failure occurring at phase boundaries.

Conclusions:

• Aging treatments effectively modify the microstructure and mechanical properties of AE45-Gd magnesium alloy.
• Aging under pressure accelerates Ostwald ripening and shortens aging time.
• The study identifies optimal aging parameters and provides insights into fracture mechanisms related to second-phase particles.