Materials science

Theoretical information
Duralumin refers to aluminum-based alloys consisting of copper, magnesium, manganese, and a small amount of silicon and iron. Duralumin is processed by thermal processing, its structure in the softened state consists of a solid solution and a second phase ( -phase CuAl ₂ , S- phase CuMgAl _{2 ) that dissolves in aluminum when the temperature increases;} these phases are tempering phases in heat treatment.

13.1 . State diagram of ( Al-Cu ) alloy system.

Di-aluminum is a process that consists of thermal treatment-finding and subsequent aging (sunny or natural).

The aim of the casting is to form a homogeneous supersaturated solid solution structure at room temperature. For example, let the alloy contain 4.5% Cu . Cu is 0.5% in Al at room temperature. When heated to point B, all copper is CuAl ₂ from to solid solution.
we get a supersaturated solid solution with a content of 4.5% at room temperature .
The aging process is performed as follows. After annealing , over time at a normal temperature of +20 ^{o C, copper atoms diffuse in a certain (100) plane of the crystal lattice in supersaturated solid solution grains, forming a layer of 2-3 atomic alloys.} These strata zones are called Guinea-Preston zones. The formation of Guinea-Preston zones leads to distortion of the crystal lattice, increasing purity and decreasing plasticity.
In the natural aging process, the Guinea-preston zone is formed for 5-7 days, during which the alloy has maximum precision. Artificial aging refers to aging at high (100,200, 300 ^o C) temperatures. In this case, the process of the formation of the Guinea-Preston zone and the strengthening of the alloy takes place quickly.
Guinea-Preston zones formed at high temperatures have the same nature as zones formed at normal temperatures, but are larger in size. For example, at 200 ^o C it will be 800 Ǻ.
An increase in temperature and an increase in wear time leads to a distortion of the crystal lattice of the solid solution and a decrease in the refinement of the alloy.