Hard aluminum is an age-strengthened aluminum alloy. It is developed on the basis of AL-CU binary alloy to improve the strength of aluminum alloy. The main alloying elements are copper and magnesium, and a small amount of manganese, chromium, antimony, etc. In the new standard, it is the 200 series. The typical chemical composition is: 2.5%~6% CU, 0.4%~2.8% MG, 0.4%~1.0% MN does not exceed 1.0%. Hard aluminum alloy products are tubes, plates, rods, wires and wires. Aluminum alloy sheets have good stamping, weldability and corrosion resistance.
AL-CU-MG aluminum alloy is a familiar Dura aluminum alloy, which is used early and widely aluminum alloy. When copper and magnesium are added together, the composite effect is much greater than the sum of the two. The number of various mesophases that appear is significantly increased with the decrease of temperature, and the effect of strengthening the effect is obvious. It is a deformed aluminum which can be heat treated. The most widely used group of alloys in alloys, characterized by a certain strength, good heat resistance, can be used at a certain high temperature, and is mainly used in ships to manufacture fasteners such as rivets and bolts.
AL-CU-MN alloy heat-resistant aluminum alloy, room temperature strength is about 400Mpa, slightly lower than LY12 alloy, but the performance at 225~250 degrees Celsius is higher than LY12 alloy, 160~180Mpa, so the aluminum alloy is commonly used 250~ The 300 degree Celsius environment is under construction.
The high strength of hard aluminum is mainly due to age strengthening. Proper quenching and aging processes are extremely important for strengthening. Hard aluminum allows a very narrow heating temperature range and must be strictly controlled.
After heating and quenching, natural aging can be carried out. After 4-7 days, high strength and hardness can be obtained. For shortening time, artificial aging can be performed. For example, at 150 degrees Celsius, the highest intensity can be achieved in half a day. The higher the aging time required, the lower the strength and hardness that can be achieved.
It is worth emphasizing that in the aluminum alloy, the intergranular corrosion of the copper-alloyed aluminum alloy is the most sensitive, the intergranular corrosion can not be avoided, and the intergranular corrosion tendency of the alloy can only be alleviated under reasonable process conditions. Outsourcing a layer of pure aluminum as a protective layer.