How strengthen aluminum?
Space achievements in many respects are defined by development of the new materials possessing the record relations of durability and rigidity to weight. And it is clear: decrease in mass of designs responds repeated economy of fuel or increase in a payload.
The most known light metal is, out of doubt, aluminum. He takes the second place after ferrous metals on consumption volume.
Most of all aluminum is used in construction, almost as much - for production of various container, it is a little less - on transport. The rest is consumed by the electrotechnical industry, mechanical engineering and other branches. In recent years nonconventional consumption of aluminum - for production of cans for drinks increased.
Most aluminum at self-summer - and rocket production is important. Any modern aircraft does not do without it.
Mechanical properties of aluminum depend on its purity and the production technology. Increase in content of impurity and plastic deformation increase its durability and hardness. Pure aluminum finds limited application: goes for production of not loaded details and designs. Use of the numerous alloys of aluminum which are characterized by high durability is much broader. On this indicator some aluminum alloys are close to high-strength stalyam.
The most often aluminum alloys alloy copper, magnesium, manganese, silicon, zinc, is more rare - lithium, nickel, the titan. One of the most known alloys on the basis of aluminum - duralumin (Al - Cu - Mg). It often use in aircraft construction for production of blades of air screws, ribs, frames etc.
high-strength aluminum alloys on the basis of the Al system - Zn - Mg - Cu Are popular. Do the high-loaded details which are generally working in the conditions of compression tension of them (longerons, a covering of planes, etc.) .
Aluminum alloys with silicon (alpaxes) are easy, strong and technological. Considering a wide circulation in the nature of silicon and aluminum, it is possible to predict against exhaustion of fields of other metals to this group of metals big future. Make large cast details of the alloyed alpaxes, for example, cases, heads of cylinders, etc.
it is possible to Strengthen aluminum and its alloys, applying the special processing methods directed to education in metal of disperse inclusions.
Such material is received, for example, pressing and agglomeration of the fine powder of aluminum oxidized from a surface. It and is called - the baked aluminum powder (BAP). It may contain up to 22% of the aluminum oxide which is evenly distributed in a metal matrix.
It is known that process of deformation of metals is followed by movement of linear defects of a crystal lattice - dislocations. Disperse particles of oxide of aluminum are an obstacle for movement of dislocations, so, strengthen metal.
And as oxide of aluminum of tugoplavka, at temperature increase it is practically not dissolved in a matrix, i.e. does not disappear, unlike other barriers on the way of dislocations. It means that SAP keeps the working capacity at more high temperatures, than pure aluminum. So, aluminum razuprochnyatsya considerably already at 200 degrees while SAP successfully works at 400, and even 500 degrees.
The Baked Aluminium Alloys (BAA) receive on the same technology. Their advantages in comparison with usual aluminum alloys - lack of foundry defects, uniform distribution of grains. From here - the improved mechanical properties.
We sum up the results. Aluminum far did not exhaust opportunities for increase of durability. We should learn about it a lot...