Best Aluminum Alloy to use
Best Aluminum Alloy to use
(OP)
In an automotive race application what aluminum alloy would you all recommend for the fabrication (CNC machining, mostly) of many of the various suspension and engine brackets on the car, such as those attaching the engine to the car (where the engine is a stressed member of the chassis), "rocker arms" whcih transfer load form the wheel, to the spring/shock combination, or those brackets attaching the suspension A-Arms to the chassis (they'll be relatevely small brackets, which will hold bolts in double shear throuh monoball bearings) and, especially, for uprights (the part at the wheel that the suspension attaches to) considering the type of loads, and relatevely low temperatures these parts see.
We had considered, and, have avaliable (most readily)
6061 T6
7075 T6
and 2024 T6
but were slightly worried about 7075 and especially 2024 being too brittle for some of the applications that will see "shock" loads, and lots of vibration.
Just wanted to get everyone's thoughts on this, cost is interestingly, not as issure, as we've just come into quite alot of various aluminum alloys quite cheaply (offcuts form an aircraft manufacturer)
Thanks.
Chuck Boulware
Chuck Boulware
We had considered, and, have avaliable (most readily)
6061 T6
7075 T6
and 2024 T6
but were slightly worried about 7075 and especially 2024 being too brittle for some of the applications that will see "shock" loads, and lots of vibration.
Just wanted to get everyone's thoughts on this, cost is interestingly, not as issure, as we've just come into quite alot of various aluminum alloys quite cheaply (offcuts form an aircraft manufacturer)
Thanks.
Chuck Boulware
Chuck Boulware





RE: Best Aluminum Alloy to use
Results:
Matl UTS x Elong
2024T6 690 ksi x % elong
6061T6 765
7075T6 913
RE: Best Aluminum Alloy to use
You use the words brittle and shock, yet neither are useful for engineering design. You want components to withstand the mechanical environment to which they are exposed, and hopefully have minimum necessary mass. This will require certain mechanical properties from the materials, such as: X minimum yield strength, Y minimum fracture toughness and Z maximum fatigue crack growth rate. All three alloys listed possess some plastic strain capacity (fracture strain > 5% for all 3), so brittle doesn't apply to them. "Shock" loading influences material strength and toughness, but should not be a significant factor for the applications you mention since the strain rate should be ~ 103 s-1 and aluminium alloys usually show little strain rate sensitivity.
Plasgears shows energy absorption potential for quasistatic loading and material with no flaws that will initiate fracture. This is a good measure for your applications, and I agree that 7075-T6 would be a good choice. If one were to include fracture-based design, the choices may change based on whether the design was in plane strain or plane stress. Also, fatigue should be considered, although 7075-T6 would still be a good choice for this criterion. Good luck.
RE: Best Aluminum Alloy to use
http://assist2.daps.dla.mil/quicksearch/
(**HUGE DOWNLOAD, ~ 42 MB!**)
or
http://www.grantadesign.com/cgi-bin/stat-tree.cgi?src=MIL5-H.xml&br=0
(individual chapters as .pdfs)
RE: Best Aluminum Alloy to use