Classification of cast aluminum alloys

Several series can be formed out of cast aluminum alloys according to their characteristics and chemical makeup. This page classifies cast aluminum alloys and is backed up by pertinent tabular data:

Because of their outstanding mechanical, machinability, and casting performance, cast aluminum alloys are the most often used kind of aluminum alloy in industry. These industries include aerospace, automotive, machinery manufacture, and other industries. Cast aluminum alloys can be separated into the subsequent series according to their chemical makeup and performance traits:

Alloys Al-Si (4xx.x series)

At over 90% of all cast aluminum alloys, the Al-Si series is the most significant category. Usually present in amounts between 5% and 20%, silicon is the primary alloying element. Castability and wear resistance of the alloy are much improved by silicon. Popular grades are A356, A380, ADC12, etc.

(wt%) composition of representative alloys:



A3566.5-7.5<0.250.25-0.45<0.35<0.6<0.35Remaining amount
A3807.5-9.53.0-4.0<0.1<3.0<1.3<0.5Remaining amount
ADC129.6-12.01.5-3.5<0.3<1.0<1.3<0.5Remaining amount


Standard characteristics of alloys with Si:

2.65 to 2.75 g/cm³ is the density.

A 150–400 MPa tensile strength

Extension: 1%–5%

60 to 130 HB Brinell hardness

Alloys Al-Cu (2xx.x series)

Usually making around 2% to 10% of the alloy, copper is the primary alloying element in Al-Cu alloys. Though it makes the alloy stronger and harder, copper also makes it less castable. Popular grades are A201, A206, etc.

alloy composition representative (weight%):

A2014.0-5.2<0.10.15-0.55<0.35<0.15Remaining amount
A2064.2-5.0<0.10.15-0.350.2-0.5<0.15Remaining amount


Standard characteristics of alloys of aluminium and copper:

2.75 to 2.85 g/cm³ is the density.

Tensile strength: between 200 and 450 MPa

Extension: 1%–5%

90 to 150 HB Brinell hardness

The Al-Mg alloys (5xx.x series)

Magnesium is the primary alloying element in Al-Mg alloys, being present in amounts between 3% and 10%. Though high quantities of magnesium might cause intergranular corrosion, it greatly improves the alloy’s corrosion resistance. Common grades are A518 and A535.

alloy composition representative (weight%):

A5187.5-8.5<0.25<0.35<0.150.1-0.4Remaining amount
A5356.2-7.5<0.15<0.15<0.050.1-0.4Remaining amount


Standard characteristics of alloys containing magnesium:

2.55 to 2.65 g/cm³ is the density.

A 250–350 MPa tensile strength

Extension: 3%–10%

60 to 90 HB Brinell hardness

The 7xx.x series of Al-Zn-Mg alloys

Zinc and magnesium concentrations in Al-Zn-Mg alloys are 3%–8% and 1%–3%, respectively. Strong, these alloys are also vulnerable to stress corrosion. Popular grades are A712, A713, etc.

alloy composition representative (weight%):

A7125.0-7.01.5-2.8<0.2<0.3<0.5<0.1Remaining amount
A7137.0-8.51.8-2.80.5-1.3<0.3<0.5<0.1Remaining amount


Characteristics of alloys of aluminium zinc magnesium:

2.75 to 2.85 g/cm³ is the density.

– 300–500 MPa tensile strength

Extension: 2%–8%

Ninety to one hundred and forty Brinell hardness

Apart from these four primary series, there exist cast aluminum alloys with specialised components, such the Al-Sn and Al-Li series, which have somewhat more specialised uses.

Among the primary variables influencing cast aluminum alloy performance are:

The total performance of the alloy is determined by the addition and content of various elements.

  1. Conditions of Solidification: Grain size and precipitate phase shape are influenced by cooling rate, which in turn impacts mechanical characteristics.
  2. Heat treatment: The strengthening effects are greatly influenced by heat treatment procedures including aging and solution treatment.

In conclusion, there exist several cast aluminum alloys, and each series emphasizes a certain performance and application area. Castings that satisfy different specifications may be made by modifying the alloy composition and streamlining the casting and heat treatment procedures. Apart from the mechanical characteristics, castability, corrosion resistance, and cost have to be carefully considered through methodical thorough analysis while choosing materials. The production of superior cast aluminum alloys will remain a major focus in the future, particularly in sectors like electronics and transportation where the need for lightweight, high-performance castings of aluminum alloys will increase, creating new chances and problems for the industry.


Related News