(1) According to the presence or absence of alloy composition, aluminum is divided into pure aluminum and aluminum alloy. The aluminum alloy is further classified into an Al-Mn alloy, an Al-Cu alloy, an Al-Si alloy, and an Al-Mg alloy according to the alloy series.
(2) According to the pressure processing ability, it can be divided into deformed aluminum and non-deformed aluminum (for example: cast aluminum).
(3) According to whether heat treatment can be strengthened, the aluminum alloy is further divided into non-heat-treated reinforced aluminum and heat-treated reinforced aluminum. Aluminum has no isomers, and pure aluminum, aluminum-manganese alloys, aluminum-magnesium alloys, etc. cannot be strengthened by heat treatment. However, alloys such as aluminum-copper and aluminum-magnesium-silicon can be strengthened by solid solution precipitation to enhance the strength, which is called heat-treated reinforced aluminum. A non-heat-treated reinforced aluminum that cannot be strengthened by solid solution aging and precipitates a strengthening phase.