Aluminium Alloys
Mechanical Properties
| Metal | UTS | 0.2% Proof | Elong | BHN | Density | ||
|---|---|---|---|---|---|---|---|
| N/mm² | TPSI | N/mm² | TPSI | % | |||
| LM25M | 130/150 | 8.0/10.0 | 80/100 | 5.0/6.5 | 2.0/3.0 | 55/65 | 2.68 |
| LM25TF | 230/280 | 15.0/18.0 | 200/250 | 13.0/16.0 | 0.0/2.0 | 90/100 | 2.68 |
| LM25TB7 | 160 | 10.0 | 80/110 | 5.0/7.0 | 2.5 | 65/75 | 2.68 |
| 2L99 | 230 | 14.8 | 185 | 12.0 | 2.0 | 80 | 2.68 |
| A356T6 | 234 | 15.0 | 166 | 10.8 | 5.0 | 70/100 | 2.68 |
| 356F | 130 | 8.4 | 120 | 80 | 2.0 | 55 | 2.68 |
| 356T6 | 207 | 13.3 | 138 | 8.9 | 3.0 | 70 | 2.68 |
| 356T7 | 214 | 13.8 | 126 | 8.1 | 3.0 | 75 | 2.68 |
| 356T51 | 159 | 10.2 | 110 | 7.1 | 3.0 | 60 | 2.68 |
| 356T71 | 172 | 11.1 | 124 | 8.0 | 3.0 | 60 | 2.68 |
| 40E | 215 | 13.9 | 170 | 11.0 | 4.0 | 60/100 | 2.80 |
| 712 | 224 | 14.4 | 172 | 11.1 | 4.0 | 75 | 2.80 |
| LM31 | 215 | 13.9 | 170 | 11.0 | 4.0 | 60/100 | 2.68 |
| Vanasil | 170 | 11.0 | 140 | 9.0 | 0.5 | 100 | - |
Comparision with International Specifications
| BSI1490 | ISO | France | Germany | USA | Aerospace |
|---|---|---|---|---|---|
| LM25 | AlSi7Mg | A-S7g | G-AlSi7Mg | A356 | BS2L99 BSL173 BSL174 |
Comparison of LM25 physical properties with 6061 & 6082 wrought aluminium
| LM25 | 6061 | 6082 | |
|---|---|---|---|
| Thermal Conductivity (% IACS) | 38.4 | 39.6 | 43.7 |
| Coefficient of linear expansion (20 - 100° C) | 22x10-6 | 24x10-6 | 23x10-6 |
| Electrical Conductivity (%IACS @ 20° C) | 39 | 43.1 | 43.7 |
| Hardness (Brinell) | 60 - 105 | 60 - 100 | 60 - 100 |
| Modulus of Elasticity | 71 | 69 | 69 |
Standard Aluminium Alloys
Silicon Magnesium Series
These alloys are the best general purpose high strength cast alloys available and can be supplied with a variety of heat treatments. They also have good salt water corrosion resistance and can be anodised to produce a thick black colour. Decorative anodising is not possible due to the metallic silicon content.
A356
An American specification that is is generally made available to meet the requirements of the American Military.
LM25
Our most commonly used cast aluminium alloy and can be supplied as cast or heat treated.
2L99
This is a more tightly controlled version of LM25 for aerospace applications.
Zinc Magnesium Series
These alloys are less easy to cast because of their high viscosity in the liquid state.
40E
This alloy is particularly suitable for castings which require flame or dip brazing. Components using this material should have uniform wall sections. To achieve corrosion resistance an additional surface treatment such as anodising or chromatic conversion is necessary. The material machines very well and is self ageing at room temperature, therefore hardening and strengthening over about three weeks.
712/LM31
These alloys are similar to 40E and are often specified for defence and space applications.
Special Aluminium Alloys
Vanasil
Sylatech pioneered the use of this difficult material. It is a very high silicon alloy which has a relatively low co-efficient of expansion which is compatible with stainless steel between -50 to +70O C (-60 to +160O F). It is used in the manufacture of gyroscopes and highly-stressed pistons.
Aluminium and copper alloys are non-magnetic whilst retaining excellent thermal and electrical conductivity. This is becoming of increasing importance in numerous applications.
