"Aircraft-Grade Aluminum” and “6063-T5”—What do they Actually Mean for Windows & Doors?

When sourcing architectural glazing, you hear the term "aircraft-grade aluminum" all the time. But with so many alloy series on the market, higher strength doesn't always mean better suited for system windows and doors.

Here is a quick technical breakdown of aluminum alloys—and why we select specific grades for building envelopes.

The Aviation Aluminum Family

2XXX Series (Al-Cu Alloy): High strength, mainly used for aircraft structural parts and engine components.

6XXX Series (Al-Mg-Si Alloy): Excellent balance of structural strength, corrosion resistance, and workability—the backbone of aircraft skins, window frames, and architectural systems.

7XXX Series (Al-Zn Alloy): Ultra-high strength and hardness, engineered for critical fuselage load-bearing structures.

8XXX Series (Al-Sn Alloy): High ductility, primarily used for aircraft riveting and welded joints.

Why Is 6XXX Series the Gold Standard for Windows & Doors?

Within the 6XXX family, each alloy has its specific application:

6061 Alloy: Extreme structural strength, used in aerospace structural parts, heavy-duty molds, and vehicle components.

6082 Alloy: Superior toughness, ideal for structural trusses and high-load frameworks.

6063 Alloy: The Ultimate Choice for Architectural Glazing. It offers unmatched extrudability, excellent corrosion resistance, and a flawless surface finish—making it ideal for both aircraft skins and premium window/door profiles.

The DEIOUX Standard: 99% Primary 6063-T5 Aluminum

At DEIOUX, 99% of our window and door systems are manufactured using prime 6063-T5 aluminum billet.

What does T5 Temper mean?

Extruded aluminum profiles are air-cooled and then subjected to precise artificial aging (heat treatment) to achieve a stable, optimal crystalline structure.

Hardness & Mechanical Integrity:

DEIOUX’s 6063-T5 aluminum achieves a Webster Hardness of 9 to 12 HW. This guarantees high wind-load resistance, structural toughness, and long-term corrosion resistance against coastal salt spray and harsh weather.

Selecting the right alloy is the first step toward building envelope excellence.