Wrought and cast alloys
industry aluminum alloys, including the "mark" aluminum, subdivided into two groups:
- aluminum alloys wrought and
- casting aluminum alloys.
The term "deformable" means, that of the aluminum alloy product is made of aluminum metal forming methods, i.e. pressing (extrusion), rolling, forging, punching.
The term "casting" means, respectively, These aluminum alloys are used for manufacturing aluminum castings.
The boundary between wrought and cast alloys
The conventional boundary between these two groups of aluminum alloys with the same alloying components is associated with the saturation limit of the solid solution at the eutectic temperature (see. drawing).
Aluminum alloys with less than the limit component at a high temperature solubility have the highest ductility and lower the strength and, Consequently, well to hot plastic working.
Aluminum alloy castability
best fluidity – the most important property casting aluminum alloys – are metals, which crystallize at a constant temperature (pure metals, eutectic alloys).
When going over the limit of solubility at high temperature is sharply increased castability. However, aluminum casting alloys should not contain more 15-20 % eutectic avoid deterioration of mechanical and technological properties.
All casting aluminum alloys can harden as a result of thermal treatment. The degree of hardening of the less, more casting aluminum alloy doped and, Consequently, in its structure over the eutectic.
The ability to heat strengthened
Wrought Aluminum Alloys are subdivided into:
- aluminum alloys, hardened by heat treatment;
- aluminum alloys, not heat-hardened.
The theoretical boundary between these groups is the saturation limit of the solid solution at room temperature (see. drawing). When the content of the alloying element less than the saturation limit of the solid solution at ambient temperature hardening by thermal treatment can not in principle be. However, in practice a small excess of this limit, thermal hardening may not be achieved due to the small amount of the hardening phase.
When fusing with other elements (Cu, Mn, At the, Mg, Si, Zn etc.) aluminum forms binary systems (alloys) with variable solubility, which makes them capable of thermally hardened by quenching and aging. However, in binary aluminum alloys Al–Cu, Al–Si, Al–Mg, Al–Zn the effect of the heat treatment is less significant, than ternary and more complicated alloys. Therefore, the primary application received at the double, and more difficult to doped alloys - aluminum alloys systems Al–Mg–Si, Al–Cu–Mg, Al–Zn–Mg.
Gulyaev AP. metal science, 1986.
Aluminium and aluminium alloys, ASM International, 1993.