7075 aluminum
Encyclopedia
Aluminium alloy 7075 is an aluminium alloy
, with zinc
as the primary alloying element. It is strong, with a strength comparable to many steels, and has good fatigue strength and average machinability, but has less resistance to corrosion than many other Al alloys. Its relatively high cost limits its use to applications where cheaper alloys are not suitable.
7075 aluminum alloy's composition roughly includes 5.6-6.1% zinc
, 2.1-2.5% magnesium
, 1.2-1.6% copper
, and less than half a percent of silicon, iron, manganese, titanium, chromium, and other metals. It is commonly produced in several heat temper
grades, 7075-O, 7075-T6, 7075-T651.
no more than 40,000 psi
(276 MPa), and maximum yield strength no more than 21,000 psi (145 MPa). The material has elongation (stretch before ultimate failure) of 9-10%.
T6 temper 7075 has an ultimate tensile strength of 74 - 78,000 psi (510 - 538 MPa) and yield strength of at least 63 - 69,000 psi (434-476 MPa). It has failure elongation of 5-8%.
The 51 suffix has no bearing on the heat treatment but denotes that the material is stress relieved by controlled stretching.
s for the American military. It is also commonly used in shafts for lacrosse
sticks, and camping knife and fork sets. French armament company PGM
uses it for its PGM Ultima Ratio
precision rifle.
Due to its strength, high density, thermal properties and its polishability 7075 is widely used in mould tool manufacture. This alloy has been further refined into other 7000 series alloys for this application namely 7050 and 7020.
in 1936. 7075 was used for the Zero fighter's air frame of the Imperial Japanese Navy
in pre-war times.
Some 7000 series alloys sold under brand names for making moulds include Alumec 79, Alumec 89, Contal, Certal, Alumould, and Hokotol.
Aluminium alloy
Aluminium alloys are alloys in which aluminium is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories...
, with zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
as the primary alloying element. It is strong, with a strength comparable to many steels, and has good fatigue strength and average machinability, but has less resistance to corrosion than many other Al alloys. Its relatively high cost limits its use to applications where cheaper alloys are not suitable.
7075 aluminum alloy's composition roughly includes 5.6-6.1% zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, 2.1-2.5% magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
, 1.2-1.6% copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, and less than half a percent of silicon, iron, manganese, titanium, chromium, and other metals. It is commonly produced in several heat temper
Tempering
Tempering is a heat treatment technique for metals, alloys and glass. In steels, tempering is done to "toughen" the metal by transforming brittle martensite or bainite into a combination of ferrite and cementite or sometimes Tempered martensite...
grades, 7075-O, 7075-T6, 7075-T651.
Mechanical properties
The mechanical properties of 7075 depend greatly on the temper of the material.7075-O
Un-heat-treated 7075 (7075-O temper) has maximum tensile strengthTensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
no more than 40,000 psi
Pounds per square inch
The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...
(276 MPa), and maximum yield strength no more than 21,000 psi (145 MPa). The material has elongation (stretch before ultimate failure) of 9-10%.
7075-T6
7075 tech sheetT6 temper 7075 has an ultimate tensile strength of 74 - 78,000 psi (510 - 538 MPa) and yield strength of at least 63 - 69,000 psi (434-476 MPa). It has failure elongation of 5-8%.
7075-T651
T651 temper 7075 has an ultimate tensile strength of at least 67 - 78,000 psi (462 - 538 MPa) and yield strength of 54 - 67,000 psi (372-462 MPa). It has failure elongation of 3-9%.The 51 suffix has no bearing on the heat treatment but denotes that the material is stress relieved by controlled stretching.
Uses
7000 series alloys such as 7075 are often used in transport applications, including marine, automotive and aviation applications, due to their high strength-to-density ratio. Its strength and light weight are also desirable in other fields. Rock climbing equipment, bicycle components, and hang glider airframes are commonly made from 7075 aluminium alloy. The bicycle industry is also using 7005 and 6061 aluminium alloys. Hobby grade RC models commonly use 7075 and 6061 for chassis plates. One interesting use for 7075 is in the manufacture of M16 rifleM16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...
s for the American military. It is also commonly used in shafts for lacrosse
Lacrosse
Lacrosse is a team sport of Native American origin played using a small rubber ball and a long-handled stick called a crosse or lacrosse stick, mainly played in the United States and Canada. It is a contact sport which requires padding. The head of the lacrosse stick is strung with loose mesh...
sticks, and camping knife and fork sets. French armament company PGM
PGM Precision
PGM Precision is a French company manufacturing high-precision rifles for military and law enforcement usages. It is the official supplier to the French Armed Forces.Models include:* PGM Hecate II...
uses it for its PGM Ultima Ratio
PGM Ultima Ratio
The PGM Ultima Ratio is a French-designed and manufactured sniper rifle. It uses the 7.62x51 mm NATO cartridge and can, depending on the variant, be chambered for several other cartridges. The PGM Ultima Ratio is intended to fulfill an anti-personnel role and is produced by PGM Précision of France...
precision rifle.
Due to its strength, high density, thermal properties and its polishability 7075 is widely used in mould tool manufacture. This alloy has been further refined into other 7000 series alloys for this application namely 7050 and 7020.
History
The first 7075 was developed by Japanese company Sumitomo MetalSumitomo Metal Industries
is a company with seat in Osaka, Japan. )It is the third largest integrated steel manufacturer in Japan withthree integrated steelworks and several other manufacturing plants.It is one of the largest manufacturers of Seamless Pipes and Tubes,...
in 1936. 7075 was used for the Zero fighter's air frame of the Imperial Japanese Navy
Imperial Japanese Navy Air Service
The Imperial Japanese Navy Air Service was the air arm of the Imperial Japanese Navy during World War II, the organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War.It was controlled by the Navy Staff of the Imperial Japanese Navy and...
in pre-war times.
Trade names
7075 has been sold under various trade names including Zicral, Ergal and Fortal Constructal.Some 7000 series alloys sold under brand names for making moulds include Alumec 79, Alumec 89, Contal, Certal, Alumould, and Hokotol.