Whether there are metals easier than aluminum?
Light metals are concentrated in the main subgroups of the first four groups of periodic system of elements. They are obliged by the name to the fact that their density is, as a rule, lower than 5 t/m 3 .
Development of production of polymeric and composite materials does not push light metals the background at all. The volume of their production continues to grow, especially it belongs to aluminum and its alloys. But there are and “more others“ light metals and alloys.
The easiest - all alkaline metals: lithium, sodium, potassium, rubidium, caesium and frantion. But in the industry from them as light material apply only lithium and that in alloys.
Lithium - the easiest of metals, it is almost twice easier than water. But, unfortunately, in pure form it is impossible to apply it as constructional material - he is too active, enters interaction both with water, and with air. And here in alloys, for example, with aluminum, - please.
Modern alyumo - lithium alloys surpass traditional alloys in many parameters, and in some cases compete with the plastic strengthened by fibers. Necessary viscosity of such alloys is provided with introduction to them of the alloying elements - manganese, zirconium and copper, the appropriate technology of production of material leading to formation of fine-grained structure and also application of the thermomechanical processing influencing uniformity of allocation of disperse phases.
Thanks to it reach a necessary combination of durability and viscosity that at the small density and high rigidity allows to consider alyumo - lithium alloys as the most perspective material for easy designs.
Alyumo - lithium alloys are interesting to the aerospace industry. It is caused by the fact that the lithium additive at the same time raises the module of elasticity and lowers alloy density, thereby promoting reduction of mass of designs.
From shchelochnozemelny metals in constructional materials use only magnesium and beryllium. Calcium and strontium in spite of the fact that they it is easier than aluminum, practically do not use.
Alloys of magnesium are numerous and are divided into two groups: foundry and deformable.
Thanks to the low density and high specific durability they are used in aerospace equipment as constructional materials. Magnesium gives them ease - magnesian alloys one third easier than aluminum.
About the fifth part of the melted magnesium use in automotive industry.
Magnesium is preferable also at production of composites with a metal matrix. The melted aluminum, for example, reacts with the reinforcing silicon carbide fibers, forming aluminum carbide. Magnesium concerning these fibers is inert.
Beryllium at the same time belongs both to lungs, and to rare metals and consequently, and to expensive. But the main lack of this metal interfering its application in equipment - high toxicity.
One more negative factor - fragility of beryllium. However it is plus at it much more.
Beryllium - one of the lightest metals. It is 1,5 times easier than aluminum and 4 times easier stainless steel. It surpasses both steel, and the titan, and aluminum in the elasticity module. It is important that its strength properties are not lost up to temperature of 800 degrees.
Despite the high cost and toxicity, beryllium use where it is irreplaceable. So, in the USA panels of a series of the Adzhena spaceships, parts of the antenna on the communication satellite “Tekset - 1“ and a reflector of the nuclear rocket engine “the Nerve - 1“ were manufactured of it.
Aluminum is in the third group of elements. There are no other metals easier than aluminum in this group. In the fourth group only silicon is lighter than aluminum. But its value is so big that he deserves separate article.
We will sum up the results. Metals it is easier than aluminum much, it is more than ten. But not all from them, alas, can replace or add it.
However everything changes...