Mechanical Properties of Cast Aluminum Bronze
Aluminum bronze is a copper-based alloy with aluminum as the main alloying element, and is available in a variety of mechanical and physical configurations. At one time it was one of the most popular materials for casting, due to its excellent mechanical properties, corrosion resistance, and strength at elevated temperatures. Since its development over 100 years ago, aluminum bronze has provided material solutions for a variety of engineering problems.
Aluminum bronzes typically are composed of 8 to 12 percent aluminum, which is the principal alloying element. That number may be increased to as much as 20 percent aluminum if the alloy is used for die-casting, compared to less than 4 percent for sand-casting operations. Nickel is also included in most alloys, up to about 8 percent, though some alloys may contain no nickel. Iron, silicon, and manganese may be added as minor elements in some alloys.
The mechanical properties of aluminum bronzes vary depending on the alloy composition, heat treatment, and other factors. Typically, they offer excellent properties. Aluminum bronzes are tensile strength at high temperatures, yield strength, and fatigue resistance. Young’s modulus of elasticity and shear modulus are also high.
Aluminum bronzes also offer excellent cryogenic properties. At cryogenic temperatures they maintain a high level of strength and toughness, while at the same time exhibiting low thermal expansion. This low thermal expansion is especially beneficial in applications involving mating dissimilar materials, such as in aircraft engines, which are subject to frequent temperature variations.
Aluminum bronze also provides a range of corrosion resistance. It is generally considered to be the most corrosion-resistant of all copper alloys, and is especially suited for marine and other salt water environments. When exposed to fresh water, it offers considerable protection from galvanic corrosion when coupled with other materials such as steel.
In general, aluminum bronzes offer many advantages over traditional steel and iron alloys. In thermally corrosive environments, aluminum bronzes provide a greater degree of protection, not only to the material but also to the components they protect. For example, they make excellent bearing housing components, protecting the bearing from corrosive elements and providing a greater level of reliability and lifespan.
The use of aluminum bronze also offers high temperature strength, allowing components to be manufactured at high temperatures without sacrificing material properties. Additionally, aluminum bronze is noted for its excellent weldability which allows the alloy to be cast and machined in a variety of shapes.
Finally, aluminum bronze is noted for its good electrical conductivity and low electrical resistance, making it a great choice for electricity generation.
In conclusion, aluminum bronze is a highly versatile engineering material that can be manufactured in a variety of forms and provides excellent mechanical, physical, and corrosion resistance properties. It can be found in a variety of applications from bearings to pumps, and from aircraft engines to power generation systems.
