7000 Aluminum: Aluminum 7075 Alloy

7000 aluminum is a high-quality, high-strength aluminum alloy that is widely used in aviation, automobiles, machinery manufacturing and other fields. Its typical grade is 7075 aluminum plate that mainly contains zinc elements. It also belongs to the aviation series. It is an aluminum-magnesium-zinc-copper alloy.

7000 aluminum alloy has high strength and hardness, and its tensile strength and yield strength are higher than other series of aluminum alloys. This high strength and hardness make the 7000 series aluminum alloy perform well when withstanding high loads and impacts, and can meet the needs of various complex application scenarios.

7000 series aluminum alloy has excellent welding performance and can be welded by various welding methods such as argon arc welding and gas shielded welding. During the welding process, the 7000 series aluminum alloy has a low melting point and is easy to perform welding operations. At the same time, its welded joints have high strength.

7000 aluminum alloys have good corrosion resistance and can resist corrosion from environmental factors such as atmosphere, seawater, acid and alkali solutions. In complex industrial environments, 7000 series aluminum alloy can effectively protect parts from corrosion damage and extend the service life of equipment.

7000 aluminum alloys have good processing properties and can be used for various mechanical processing operations such as milling, drilling, planing, and grinding. At the same time, the heat treatment performance of 7000 series aluminum alloy is also good, and its strength and other mechanical properties can be further improved through heat treatment.

Zinc is the main alloy element in the aluminum 7075 alloy . Adding magnesium to an alloy containing 3%-7.5% zinc can form MgZn2 with significant strengthening effect, making the alloy's heat treatment effect far better than that of aluminum-zinc binary alloy. Increasing the zinc and magnesium content in the alloy will further increase the tensile strength, but its ability to resist stress corrosion and spalling corrosion will decrease.

After heat treatment, 7075 aluminum can achieve very high strength properties. 7075 aluminum sheet generally adds a small amount of copper, chromium and other alloys. Among this series, 7075-T651 alloy is particularly top-grade and is known as the best product among aluminum alloys. It is widely used in the aerospace, mold processing, mechanical equipment, and tooling fixtures. It is especially used to manufacture aircraft structures and high-stress structures that require high strength and strong corrosion resistance.

Original Source:https://www.aircraftaluminium.com/a/7000-aluminum-aluminum-7075-alloy.html

7150 Aircraft Aluminum’s Corrosion Resistance Performance

 7000 high-strength aluminum has high specific strength and good toughness, and is widely used in the aerospace field. However, high-strength aluminum alloys are prone to local corrosion such as pitting corrosion, intergranular corrosion, and exfoliation corrosion,etc.

Due to the large stress that the material bears, stress corrosion cracking is prone to occur, which brings hidden dangers to aviation safety. Therefore, the stress corrosion research of 7000 series aluminum alloy has attracted much attention. Appropriate heat treatment conditions can be selected to improve the stress corrosion resistance of 7000 aluminum alloy.

The characteristic of aluminum alloy stress corrosion is intergranular fracture, which is dominated by the precipitation structure of aluminum alloy grain boundaries. This type of corrosion requires the grain boundary to meet a condition, that is, the grain boundary is an anode relative to the structure around the grain boundary, so that the corrosion can selectively extend along the grain boundary.

For 7000 aluminum alloy, the anode zone is η phase (MgZn2). The stress corrosion performance of 7000 can be improved by heat treatment. It is to adjust the morphology and distribution of η phase on the grain boundary to achieve their goals.

For example, the η phase of the 7150 aircraft aluminum alloy in the T6 Temper is continuously distributed in the grain boundary, so the intergranular corrosion is very easy to develop in depth, thereby causing stress corrosion cracking.

The grain boundary of 7150 aluminum plate with T77 temper treated with regression and re-aging is intermittently distributed with coarse η phase, which will inhibit the further development of corrosion, thereby improving the alloy's stress corrosion resistance.

For the microstructure of 7000 aluminum alloy, the intragranular precipitation structure dominates the strengthening, and the grain boundary precipitation structure dominates the corrosion. The 7150 aluminum plate in the T6, T77, T76 and T76+T6 has different corrosive properties.

Original Source:https://www.aircraftaluminium.com/a/7150-aircraft-aluminums-corrosion-resistance-performance.html