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The Mechanical Properties of 6061 Aluminum Sheets

Aluminum is lightweight, relatively strong and machines easily. University researchers investigate the properties of one alloy, called 6061, to determine its suitability for various uses. The investigation of aluminum sheets is not new, but rather has been ongoing for a number of years. For example, aluminum sheet has been used for aircraft panels since the 1930s due to its light weight. Another possible use for the 6061 alloy is auto body panels, since it weighs half than comparable steel panels. As of 2010, researchers have discovered that the 6061 alloy has both good and bad points.

Springback Concerns
- Aluminum alloy 6061 sheet has been investigated to make auto bodies. Aluminum weighs roughly half as much as steel, but researchers concur that springback poses a problem. Springback is a phenomena exhibited in many metals. Think of it this way: If you bend a piece of soft copper wire, it will hold its shape after bending. If you bend a piece of spring steel wire, it will spring back to its original form. Aluminum has about twice the springback rate of steel. This presents problems for the mass production of auto body panels. For example, after stamping a fender, the aluminum will try to spring back to a flat section. Researchers are currently investigating methods to overcome the springback problem.
Welding Characteristics
- Researcher Y.M. Zhang and colleagues investigated the welding properties of 6061 extensively in October 2000. They discovered that while it possesses good welding characteristics, bad characteristics exist as well. For one, the welds hold air pockets, called porosity. For another, the welds are prone to cracking, due to heat embrittlement. Mr. Zhang and his colleagues developed a process to overcome this, by welding both sides of the seam at once, by using a dual arc welding system. One arc welding tip is held below the seam, and another tip welds from the top side. This process is not yet perfected, but research is ongoing into overcoming welding problems.
Temper Characteristics
- The Aluminum Company of America (ALCOA) provides temper specification for its 6061 alloy. Tempering is the process of heat treating a metal. After the metal is poured, it is subjected to heating and cooling. This changes the properties of the metal. Many different types of heat treating are available for 6061, each imparting a unique characteristic to the aluminum. For example, in one type of 6061, called 6061-T1, the formability is high, meaning is is well suited to be formed with no issues. However, with another type, called 6061-T6, the formability factor is low, meaning it is not well suited to be formed.

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