Duralumin - Chemical Composition, Mechanical Properties and Common Applications

Topics Covered

Introduction
Chemical Composition
Mechanical properties
Manufacturing process
Applications
References

Introduction

Duralumin is a strong, lightweight alloy of aluminium discovered in 1910 by Alfred Wilm, a German metallurgist. It is relatively soft, ductile and easily workable under normal temperature. The alloy can be rolled, forged and extruded into various forms and products. The tensile strength of duralumin is higher than aluminum, although its resistance to corrosion is poor. The electrical and heat conductivity of duralumin is less than that of pure aluminum and more than that of steel. It was initially used in rigid airship frames, and its heat-treatment methods and composition were wartime secret. With the introduction of new monocoque construction methods in early 1930s, duralumin was widely used in the aircraft industry.

The light weight and high strength of duralumin when compared to steel enabled its application in aircraft construction. However, a special laminated form of duralumin called alclad is used in the aircraft industry as it tends to lose strength during welding.

Chemical Composition

The chemical composition of duralumin is outlined in the following table.

Mechanical properties

The mechanical properties of duralumin are displayed in the following table.

Manufacturing process

Duralumin can be easily forged, casted and worked with respect to its low melting point. It is annealed between temperatures ranging from 350 to 380°C (662 to 716°F) and air-cooled. The alloy now becomes plastic and can be readily worked and formed into desired sections. The alloy is then heat treated at 490 to 510°C (914 to 950°F) to enhance its tensile properties. Following this, duralumin is quenched and hardened.

Applications

The following are some of the major applications of duralumin:

• Aircraft frames
• Frames of speedboats and automobiles
• Lightweight guns like the FAMAS type 97
• Surgical and orthopedic work
• Manufacturing components of measuring instruments

References

• Duralumin – Britannica
• Dural^® - Aluminum/Copper/Magnesium – Goodfellow
• Introduction to Basic Manufacturing Processes and Workshop Technology – Google Books
• Duralumin – Write Work
• Duralumin – Wordpress