Casting alloys of aluminum-silicon-copper

Unlike deformable aluminum alloys, casting alloys have a much higher content of alloying elements.

Copper and silicon in aluminum

Of all the alloys of aluminum casting alloys, aluminum-copper-silicon have the widest application. These alloys have good castability properties. The combination of silicon and copper allows to apply heat treatment to improve the mechanical properties.

The amount of these alloys like copper, and silicon varies very widely. Therefore, in some alloys, aluminum-copper-silicon, copper predominates, while in others - silicon.

В этих сплавах:

  • Copper provides strength, a
  • Silicon improves the casting properties and reduces the hot cracking.

Alloys of aluminum-silicon-copper with a copper content of more than 3-4 % are thermally hardening. However, the heat treatment is usually used only, if these alloys also contain magnesium, which increases their susceptibility to heat treatment.

Сплавы с большим содержанием кремния (более 10 %) имеют низкое термическое расширение, which is an advantage for products, operating at elevated temperatures. When the silicon content exceeds 12-13 %, up to 22 %, present in the alloy of silicon primary crystals. When these crystals are properly distributed, they provide high wear resistance alloy. From these hypereutectic alloys is manufactured, for example, Automobile engine block.

Effect of magnesium

Многие сплавы системы Al-Si-Cu содержат также магний: АЛ3, AL4M, AK5M2, AL5, AL5-1, AL6, AK7M2, Ak4M4, AL32. This gives them a high thermal stability with operating temperatures 250-275 oC. These alloys are inferior to the alloys Al-Si and Al-Si-Mg casting properties of, corrosion resistance and tightness. Does not require modification and pressurized crystallization.

A casting aluminum alloy 380.0

Формула сплава: 8,5Si-3,5Cu

Химический состав:

  • copper: 3,0-4,0 %;
  • magnesium: 0,10 % макс.;
  • марганец: 0,50 % макс.;
  • кремний: 7,5-9,5 %;
  • iron: 2,0 % max. $
  • nickel: 0,50 % макс;
  • zinc: 3,0 % макс.;
  • lead: 3,5 % макс.;
  • другие: 0,50 % макс.;
  • алюминий: остальное.

Effect of impurities

High iron content reduces the plasticity. The impurity content can reach relatively high values ​​before it starts to manifest their serious impact.

Типичные механические свойства:

  • прочность на растяжение: 330 MPa;
  • предел текучести: 165 MPa;
  • относительное удлинение: 3 %;
  • коэффициент Пуассона: 0,33;
  • модуль упругости: 71,0 GPa.

Физические свойства:

  • плотность: 2,71 g / cm3;
  • температура ликвидус: 595 ºS;
  • температура солидус: 540 oC.

Технологические свойства:

  • the melting temperature: от 650 by 760 ºS;
  • температура разливки: от 635 by 705 ºS;
  • температура отжига для повышения пластичности: 260-370 oC,
    excerpt - 8 hours, охлаждение с печью или на спокойном воздухе;
  • температура отпуска для снятия внутренних напряжений: 175-260 oC,
    excerpt - 4-6 hours, in still air cooling.

aluminum-silicon phase diagram, and aluminum-copper

fazovaya-diagramma-alyuminiy-kremniyThe phase diagram of aluminum-silicon

The phase diagram of aluminum-copper

Источник: Aluminum and Aluminum Alloys, ASM International, 1996