Wrought Aluminum Alloys (2)
High Electrical Conductivity.
Pure aluminum and some of its alloys have exceptionally high electrical conductivity (i.e., very low electrical resistivity), second only to copper among common metals as conductors.
Pure aluminum and some of its alloys have exceptionally high electrical conductivity (i.e., very low electrical resistivity), second only to copper among common metals as conductors.
Excellent Reflectivity.
Aluminum with appropriate surface treatment becomes an excellent reflector and does not dull from normal atmospheric oxidation.
High Fracture Toughness and Energy Absorption Capacity.
Many aluminum alloys are exceptionally tough and excellent choices for critical applications where resistance to unstable crack growth and brittle fracture are imperatives. Alloys of the 5xxx series, for example, are prime choices for liquefied natural gas (LNG) tankage. And special high-toughness versions of aerospace alloys, such as 2124, 7050, and 7475, replace the standard versions of these alloys for critical bulkhead applications.
Superior Cryogenic Toughness.
Aluminum alloys, especially of the 3xxx, 5xxx, and 6xxxseries, are ideal for very low temperature applications because the ductility and toughness as well as strength of many alloys at subzero temperatures are as high as or higher than at room temperature, even down to near absolute zero. As noted above, the 5xxx series alloys
Aluminum alloys, especially of the 3xxx, 5xxx, and 6xxxseries, are ideal for very low temperature applications because the ductility and toughness as well as strength of many alloys at subzero temperatures are as high as or higher than at room temperature, even down to near absolute zero. As noted above, the 5xxx series alloys
are regularly used for liquefied gas tankage operating at temperatures from 150 to 452 F
( 65 to 269 C)
Fatigue Strength.
On an efficiency basis (strength to density) the fatigue strengths of many aluminum alloys are comparable to those of steels.
( 65 to 269 C)
Fatigue Strength.
On an efficiency basis (strength to density) the fatigue strengths of many aluminum alloys are comparable to those of steels.
Low Modulus of Elasticity.
Aluminum alloys have elastic moduli about one-third those of steels (about 10 106 psi vs. about 30 106 psi), so they absorb about three times as much elastic energy upon deformation to the same stress. They also deflect three times more under load (see Section 2.3).
Aluminum alloys have elastic moduli about one-third those of steels (about 10 106 psi vs. about 30 106 psi), so they absorb about three times as much elastic energy upon deformation to the same stress. They also deflect three times more under load (see Section 2.3).
Superior Workability.
Aluminum alloys are readily workable by virtually all metalworking technologies and especially amenable to extrusion (the process of forcing heated metal through shaped dies to produce specific shaped sections). This enables aluminum to be produced in a remarkable variety of shapes and forms in which the metal can be placed in locations where it can most efficiently carry the applied loads.
Aluminum alloys are readily workable by virtually all metalworking technologies and especially amenable to extrusion (the process of forcing heated metal through shaped dies to produce specific shaped sections). This enables aluminum to be produced in a remarkable variety of shapes and forms in which the metal can be placed in locations where it can most efficiently carry the applied loads.
Ease of Joining.
Aluminum alloys may be joined by a very broad variety of commercialmethods, including welding, brazing, soldering, riveting, bolting, and even nailing in additionto an unlimited variety of mechanical procedures. Welding, while considered difficult bythose familiar only with joining steel and who try to apply the same techniques to aluminum, is particularly easy when performed by proven techniques such as gas–metal arc welding (GMAW or MIG) or gas–tungsten arc welding (GTAW or TIG).
Aluminum alloys may be joined by a very broad variety of commercialmethods, including welding, brazing, soldering, riveting, bolting, and even nailing in additionto an unlimited variety of mechanical procedures. Welding, while considered difficult bythose familiar only with joining steel and who try to apply the same techniques to aluminum, is particularly easy when performed by proven techniques such as gas–metal arc welding (GMAW or MIG) or gas–tungsten arc welding (GTAW or TIG).
Versatile Array of Finishes.
Aluminum can be finished in more ways than any other metal used today, including a variety of techniques that build upon its strong oxide coating and employ coloring, plus more conventional means such as painting and enameling.
Aluminum can be finished in more ways than any other metal used today, including a variety of techniques that build upon its strong oxide coating and employ coloring, plus more conventional means such as painting and enameling.
Ease of Recyclability.
Aluminum and its alloys are among the easiest to recycle of any structural materials. And they are recyclable in the truest sense, unlike materials which are reused but in lower quality products: Aluminum alloys may be recycled directly back into the same high-quality products like rigid container sheet (cans) and automotive components. Through such recycling, the life-cycle assessment advantages for aluminum are optimized.
Aluminum and its alloys are among the easiest to recycle of any structural materials. And they are recyclable in the truest sense, unlike materials which are reused but in lower quality products: Aluminum alloys may be recycled directly back into the same high-quality products like rigid container sheet (cans) and automotive components. Through such recycling, the life-cycle assessment advantages for aluminum are optimized.
J. G. Kaufman
Kaufman Associates
Columbus, Ohio
Mechanical Engineers’ Handbook: Materials and Mechanical Design, Volume 1, Third Edition.
Edited by Myer Kutz
Copyright 2006 by John Wiley & Sons, Inc.
for more details and updates about autocad simple tutorial please visit.........
www.autocadsimpletutorial.blogspot.com
---or---
Posting Komentar untuk "Wrought Aluminum Alloys (2)"