New Hampshire, USA

Manchester, New Hampshire USA

information: questions alloy

An alley is the space between two buildings. An alloy is a combination of two or more metals.

We answer a lot of mail regarding aluminum parts and alloy parts. There are some who feel that alloy parts are not aluminum or that alloy is weaker and heavier. The terms are quite commonly used, although technically incorrect, interchangeably. Aluminum in its pure form is highly ductile. This means it is easily shaped by bending. Aluminum is alloyed with other elements such as copper, magnesium, silicon, manganese, and zinc. When alloyed, the mechanical strength of aluminum is enhanced.

The Aluminum Association has determined standard alloys. These alloys are designated using a four digit number such as 6061 or 7075 followed by a temper designation such as T3 or T6. T3 means that the alloy was solution heat treated, cold worked, and then naturally aged (age hardened). A solution heat treatment followed by artificial aging is indicated by T6. The "most pure" aluminum alloy commercially available is 1100. This is used in low grade cooking utensils.

The alloys used to make GPM parts and accessories are 6061-T6 for suspension components, and 7075-T6 for chassis plates and other strength critical parts.

The table below lists a few common alloys and their uses.

Composition (percent weight) Tensile
Copper Magnesium Manganese Other PSI PSI % Elongation
in 2 inches
of material
1100 0.12 0.0 0.0 0.0 13000 5000 35 sheet metal work,
cooking utensils,
bus and truck use
3003 0.12 0.0 1.2 0.0 16000 6000 30
5052 0.0 2.5 0.0 0.25 Chromium 28000 13000 25
2014 4.4 0.5 0.8 0.8 Silicon 70000 60000 13 General Structures
6061 0.3 1.0 0.0 0.6 Silicon,
0.2 Chromium
45000 40000 12 Towers, Aircraft, Bicycles
7075 1.6 2.5 0.0 5.6 Zinc,
0.23 Chromium
83000 73000 11 Aircraft structural parts

The table shows us that as other elements are added to aluminum, the resistance to bending (ductility) is enhanced. The tensile (pulling or tension) strength generally rises as does the yield strength.