2024 aluminum
Encyclopedia
Aluminium alloy 2024 is an aluminium alloy
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 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...

 as the primary alloying element. It is used in applications requiring high strength to weight ratio, as well as good fatigue
Metal Fatigue
Metal Fatigue , is a futuristic science fiction, real-time strategy computer game developed by Zono Incorporated and published by Psygnosis and TalonSoft .-Plot:...

 resistance. It is not weldable
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...

, and has average machinability
Machinability
The term machinability refers to the ease with which a metal can be machined to an acceptable surface finish. Materials with good machinability require little power to cut, can be cut quickly, easily obtain a good finish, and do not wear the tooling much; such materials are said to be free machining...

. Due to poor corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...

 resistance, it is often clad with aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 or Al-1Zn for protection, although this may reduce the fatigue strength.

Basic properties

Aluminum alloy 2024 has a density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 of 2.78 g/cm³ (0.1  lb/in³), electrical conductivity of 30% IACS, Young's Modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 of 73 GPa (10.6 Msi) across all tempers, and begins to melt at 500 °C (932 °F).

2024 aluminum alloy's composition roughly includes 4.3-4.5% 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...

, 0.5-0.6% manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...

, 1.3-1.5% 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...

 and less than a half a percent of silicon, zinc, nickel, chromium, lead and bismuth.

Mechanical properties

The mechanical properties of 2024 depend greatly on the 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...

 of the material.

2024-O

2024-O temper aluminium has no heat treating. It has a maximum tensile strength
Tensile 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...

 of 30-32 ksi (207-220 MPa), and maximum yield strength of no more than 14,000 psi (96 MPa). The material has elongation (stretch before ultimate failure) of 10-25%, this is the allowable range per applicable AMS specifications.

2024-T3

T3 temper 2024 sheet has an ultimate tensile strength of 58-62 ksi (400-427 MPa) and yield strength of at least 39-40 ksi (269-276 MPa). It has elongation of 10-15%.

2024-T351

T351 temper 2024 plate has an ultimate tensile strength of 68 ksi (470 MPa) and yield strength of 41 ksi (280 MPa). It has elongation of 19%.

Uses

Due to its high strength and fatigue resistance, 2024 is widely used in aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 structures, especially wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

 and fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...

structures under tension. Additionally, since the material is susceptible to thermal shock, 2024 is used in qualification of liquid penetrant tests outside of normal temperature ranges.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK