Aluminum master alloys help metallurgists fine-tune alloys to create materials that are stronger, lighter, and more easily processed
Aluminum is the most abundant metallic element in the Earth’s crust—it’s even more common than Iron. In its pure form, though, it’s soft and malleable. It needs to be alloyed with other elements, including Iron, Zinc, Silicon, Copper, and Magnesium, to provide it with the strength it needs to be useful in industrial applications.
Aluminum alloys are versatile because properties like stiffness, strength, corrosion resistance, weldability, and machinability can be adjusted during the alloying process. When creating an Aluminum alloy, master alloys are used to fine-tune the composition. Master alloy is a term used to refer to a semi-finished product that includes a base metal (such as Aluminum or Copper) combined with a high percentage of one or two other elements.
Although elements can be added to an alloy in their pure form, using pure elements often isn’t cost-effective or efficient because they may have a poor yield or take longer to dissolve. Also, some active elements are easier to handle when they are combined with at least one other element. Using a master alloy can help control these factors. Master alloys often are engineered so they will dissolve quickly and at lower temperatures, which saves time, energy and money—especially when alloying metals with high melting points, such as Iron, Titanium, and Nickel. Master alloys are produced in various shapes: slab, waffle, ingot, and lumps, depending on the process used to manufacture them and their desired purpose.
Aluminum master alloys are specifically used as grain refining, modifying or hardening agents. Aluminum is widely used as a deoxidizer. It can control austenite grain growth in reheated steels and is effective at controlling grain growth prior to quenching. Grain refiners, such as master alloys containing the combination of Aluminum, Titanium, and Boron (AlTiB), give slabs or billets a finer and more uniform grain structure, which improves the casting’s mechanical strength and helps prevent cracking during subsequent processing.
Hardeners, such as Aluminum-Zirconium, Chrome-Aluminum, Manganese-Aluminum, or Aluminum-Copper master alloys, contain the hardening element (such as Zirconium) in a high concentration and change the composition of alloys to enhance strength. Modifiers, such as Aluminum-Silicon master alloys, are used to alter the micro-structure of the alloy, increasing durability and machinability. Beyond grain refiners, modifiers, and hardeners, Aluminum master alloys also can be used to achieve more specialized properties in a finished alloy—such as electrical conductivity.
Aluminum master alloys from Brooklyn, New York-based Belmont Metals enable casting houses and ingot manufacturers to overcome problems associated with alloying. Adding elements to molten metal in the wrong quantities can cause negative side effects, including damage to equipment and inconsistent performance of the finished products. Choosing the correct master alloy involves evaluating factors such as melting and casting practices and amount of secondary aluminum in the melt. In addition, the various forms of master alloys have different microstructures, which can have an effect on production. A trusted alloy manufacturer can help analyze the composition and ensure the finished alloy has the desired mechanical and physical properties needed to perform at a high level.