Light alloys and light metals have low density and high strength-to-weight ratios. They are generally characterized by low toxicity in comparison to heavy metals, although beryllium is an exception.
Types of Light Metals
Light weight metals include aluminum, magnesium, titanium, and beryllium alloys.
- Aluminum and aluminum alloys are lightweight, non-ferrous metals with good corrosion resistance, ductility, and strength. Aluminum is relatively easy to fabricate by forming, machining, or welding. This metal is a good electrical and thermal conductor. Aluminum is also useful as an alloying element in steel and titanium alloys. Aluminum alloys are versatile metals with applications in almost every industrial and commercial segment.
- Magnesium and magnesium alloys are non-ferrous metals with low density (relatively high strength to weight ratio), good ductility, moderate strength, and good corrosion resistance. Magnesium and magnesium alloys are used in a variety of industries as well as in aircraft, marine, and power tool applications.
- Titanium and titanium alloys are non-ferrous metals with excellent corrosion resistance, good fatigue properties, and a high strength-to-weight ratio. Titanium's properties result in the use of titanium and titanium alloys in aircraft or airframe parts, jet engine super-alloy components, corrosion resistant chemical process equipment (valves, piping, and pumps), prostheses or medical devices, and marine equipment.
- Beryllium has the second lowest density compared to the common structural light metal alloys (Al, Mg, and Ti). Magnesium has a density of 1.74 g/cc and aluminum has a density of 2.7 g/cc. Beryllium's unusually high Young's modulus (287 GPa) is a useful property in structural applications. The high modulus and low density make beryllium alloys useful for aerospace applications.
Beryllium has superior specific heat dissipation (heat dissipation per unit mass) compared to other metals because of beryllium's high specific heat and thermal conductivity. Beryllium also has a low thermal expansion coefficient (CTE). Many heat sinks and other thermal management products are fabricated from beryllium, beryllium alloys, and beryllium oxide ceramics due to beryllium's excellent thermal properties.
Specifications and Properties
Selecting metals and metal alloys requires an analysis of the desired specifications. Dimensions to consider include outer diameter (OD), inner diameter (ID), overall length, and overall thickness. Other specifications of importance (based on application) include product shape, tensile strength, yield strength, melting point, conductivity, corrosion resistance, ductility, and malleability. These properties differ based on the material or alloy composition.
Uses for Light Metals
Light metals are utilized most readily for operations and materials that require both good performance properties and lighter materials. Common uses include aerospace, marine, chemical process, and medical applications.