Refractory metals and alloys

Refractory metals, as the very definition of these alloys sounds, are very difficult to melt. Metals that are difficult to melt are called refractory. The classification of these metals is quite peculiar: some manufacturers classify alloys with a melting point of 1650 ° Celsius and higher, others with a temperature of more than 2000 ° C.

The classic refractory metal is the 5 main elements of the periodic system:

tantalum;

niobium;

tungsten;

molybdenum;

rhenium.

In addition to the category of refractory metals, the melting point of which is from 1650 to 1800 degrees Celsius can be attributed. This group includes alloys based on titanium, chromium, zirconium, rhodium, hafnium, iridium, vanadium and some other elements.

Refractory alloys are sufficiently resistant to melting, which is explained by their atomic structure. Atoms contain s and d-type electrons. It is d-electrons that provide the strength of the interatomic bond, therefore, an extremely high temperature is required to break this “bond”.

Application

The scope of use of materials such as refractory metals and alloys is quite extensive. Rolled metal products made from refractory alloys are in demand in many sectors of the national economy. In this case, the application will not necessarily be associated with high temperatures.

You may need to buy refractory alloys for industries such as:

mechanical engineering;

machine tool industry;

shipbuilding;

the aerospace industry;

· Atomic industry;

Energy and nuclear industry;

metallurgical industry.

For a variety of refractory alloys, the price can vary significantly depending on the alloying components included in the composition, which provide the unique properties of a particular material.

Features and properties of some metals

The most refractory material is considered to be tungsten, which is practically not used in its pure form. Nickel, iron and copper additives, as well as rhenium or thorium are added as alloying components to the tungsten alloy.

Rhenium improves corrosion resistance, thorium makes the material more reliable and durable, nickel guarantees high density. In tungsten alloys directly the main component is no more than 75-80%, the rest is additives.

The properties of tungsten are quite unique, because this metal is both hard and resistant to melting. That is why alloys based on it are also called “military” ones: they are used for the production of missiles, shells, armor-piercing cartridges, and various weapons equipment.

Molybdenum alloys can be alloyed in much smaller “doses” – only about a few percent. However, the final properties of the alloy do not “suffer” at all. The main alloying elements of molybdenum are titanium, zirconium and tungsten.

In the latter case, the alloy turns out to be quite inert, with significant resistance. Molybdenum-based steels are used in molds for casting zinc elements, in the production of rolled pipes, and in the automotive industry.

Alloys based on niobium and tantalum are in demand in electrical engineering for the production of capacitors. Rocketry, shipbuilding, nuclear power, high-precision electronics, the medical industry – all of these industries use niobium and tantalum refractory alloys to a greater or lesser extent.

The rarest of the refractory metals and at the same time extremely expensive is considered rhenium. Its extraction is labor-intensive and very complex technologically. There is not so much of it in the earth’s crust, so rhenium always acts as an alloying element.

Often it is added to copper and platinum alloys: rhenium improves the strength of soft metals and allows forging to be used in processing. The main area of ​​use is related to nuclear power, chemical and electronic industries.