China Promotes R&D of Superalloys for Aero Engines to Enhance Aerospace Material Performance
Ultra-high-strength aluminum alloys typically refer to aluminum alloys with a yield strength above 500 MPa, commonly known as the 7-series super-hard aluminum. These alloys were originally developed for aerospace applications and have become the main structural materials for military and civilian aircraft, accounting for 70-80% of aircraft structural parts. They have replaced expensive titanium alloys in many fields and become indispensable lightweight structural materials. With the development of aerospace, nuclear industry, and transportation, higher requirements are placed on the comprehensive performance of structural parts. The new generation of ultra-high-strength aluminum alloys is favored for their light weight, high strength, high toughness, high fracture toughness, and resistance to stress corrosion.
Aluminum alloys, as mature lightweight and high-strength materials, are widely used in aerospace, with higher specific strength and better processing performance than steel. The aerospace field mainly develops high-strength, high-toughness, and corrosion-resistant aluminum alloy materials to meet stringent application conditions. The 2000 and 7000 series aluminum alloys are the most commonly used types. Through innovative production processes such as powder metallurgy and spray forming, the performance of aluminum alloys has been further improved. However, stress corrosion remains a major challenge in aluminum alloy applications.
The 2000 series aluminum alloys are mainly composed of aluminum, copper, and magnesium. The addition of copper improves the strength, heat resistance, and processing performance but reduces corrosion resistance. Therefore, the surface is usually clad with pure aluminum or 6000 series aluminum alloys to enhance corrosion resistance. The 7000 series aluminum alloys are mainly composed of aluminum, zinc, magnesium, and copper, and can be strengthened through heat treatment to enhance toughness. Although the 7000 series aluminum alloys have high strength and weldability, they also have high stress corrosion sensitivity. Adding trace elements such as chromium, manganese, and molybdenum can improve this issue.
