Tungsten, Silver and Copper Alloys, UK

General Characteristics:	Mallory Tungsten Heavy Alloys are not true alloys, since they are made by powder metallurgy techniques. Tungsten powder is first blended with other metal powders (typically copper and nickel) and a binding agent. This mixture is then pressed to the required shape, allowing for shrinkage during the final processing. These pressed components are subjected to a furnacing operation, to remove the bonding agent and to sinter the powder particles together.

50% Heavier Than Lead:	Tungsten Heavy Alloys, with densities between 16.9 and 18.1 g/cm³, represent the heaviest materials generally available to the engineer. Whilst more dense materials exist (Uranium 19.05g/cm³, Tungsten 19.32g/cm³, Gold 19.30g/cm³ and platinum group metals with densities ranging from 20.50 – 22.48g/cm³), their use is restricted by availability, workability and cost.

Strength of Steel:	Whilst lead and pure tungsten are dense materials, their mechanical properties are not particularly attractive to the engineer. Lead of course is mechanically weak and pure tungsten has very poor ductility. Tungsten Heavy Alloys exhibit tensile strengths between 700 – 1000 MN/m² and have ductilities between 5 – 20%. These properties mean that load bearing components can be made of Mallory Heavy Alloys.

Readily Machinable:	Because the materials are produced by powder metallurgy techniques, it is possible, either to press components to shape, or to cut and shape material prior to sintering. This ability to produce parts very close to the required size, reduces the amount of final machining necessary to produce the finished component. Unlike pure tungsten which requires to be machined at elevated temperature, tungsten heavy alloys can be machined conventionally, without much difficulty.

	Associated Data – Mallory Tungsten-Based Materials
	u Machining Recommendations 1300 : 538.

Corrosion Resistant:	Mallory Heavy Alloys have excellent resistance to most of the common corrosive agents; in dilute solutions of hydrochloric acid; resistance to attack is up to twice that of 18/8 stainless steel.

Stable At Around 1000^oC:	Heavy Alloys typically remain stable up to temperatures of 1000^oC and good oxidation resistance up to 400^oC.

Forms of Supply:	Mallory Heavy Alloys can be supplied in bar form in lengths up to 12”. Square, round and rectangle sizes are available in rough oversize or turned or ground to exact requirements. Components to customers drawings can also be produced.

Applications:	The unique properties of Mallory Heavy Alloys together with its machinabilty make it one of the more versatile materials available to the engineer. Its uses can be broadly split into three categories yet new applications are still being explored.

1. Density	The high density and strength of the Mallory 1000range of materials make it an ideal choice in the use of balance weights in:

	· aircraft mass balance weights
	· control surface balance weights
	· counter balance weights
	· gymbol weights
	· flywheel weights
	· crankshafts weights, particularly high performance racing engines
	Associated Data – Mallory Heavy Alloy for Dynamic Balancing 1300 : 534.

2. Energy Absorption	The densities of theses Mallory Heavy Alloys make it a suitable material where energy absorption is required. It is used to mount sensitive or quiet running equipment to eliminate vibration. The same anti-vibration characteristics are employed in Mallory No Chat which is an excellent tool shank material for boring bars and grinding quills. The electronic industry also uses heavy alloys in transducers and accelerometers.

	Associated Data – Mallory No Chat Vibration damping tool shank material 1300 : 530

3. Radiation Shielding	Because tungsten heavy alloy is much denser than other shielding materials a reduction in the overall volume of a shield is possible allowing a saving in space and in many cases weight. It is used throughout medical and nuclear industries:

	· collimators
	· Directional shields on radiation detection equipment
	· Gamma and X-ray camera shutters
	· Isotope transports
	· Radiotherapy equipment
	· Syringe shields and containers

	Associated Data – Mallory 1000 for Radiation Shielding (narrow beam radiation data and graph) 1300 : 536

	Other major applications of heavy alloys are the manufacture of dart barrels and penetrators in the armament industry.

Anviloy:	The addition of Molybdenum to heavy alloy increases its hardness and tensile strength making it a strong extrusion die and die casting tool. Applications are mainly in the automobile industry as inserts in the casting of many different components including wheels and pistons.

	Associated Data – Anviloy data sheet 1300 : 520