Can aluminum be hardened?

I have a ruler made from thin (.02") stainless steel. I'm wondering if I
can get the same stiffness and springiness from aluminum sheet. I don't
mind increasing the thickness, but I don't want to increase the overall
weight. Are there types of aluminum that have the same qualities as
hardened steel?
Reply to
Ken
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Would a reinforcing rib down the center of the ruler be objectionable? How about holes to lighten the ruler to meet your weight objective?
Have you considered titanium?
Reply to
Mark Thorson
The application is for the base of a snowboard so a rib and holes are out of the question. I still want it to be able to flex. I like the spring-like flexibility of the ruler. I have thought to try titanium, but like stainless it isn't cost effective. If I'm not mistaken, aluminum and steel have approximately the same specific strength. But do they also have the same specific modulus. Steel can be hardened, but I don't know if there is hardened aluminum.
Reply to
Ken
No.
Michael Dahms
Reply to
Michael Dahms
As you know, you can buy bicycles with steel or aluminum frames ( and titanium and carbon fiber composite, and some other materials).
So, it is certainly possible to substitute a larger diameter aluminum tube or thicker tube for steel in a sporting goods structure.
It helps to be more direct about the applicatin than calling it a "ruler", as that creates a false impression.
There are no aluminum alloys that have the same qualities as hardened steel, unless it is a pretty inferior hardened steel, and then only the strength may match, not the elastic stiffness(Young's modulus).
You speak as if you know that some steel strip works, you have no materials understanding, and you would like to find something lighter than steel for your snowboards..... and not have to understand much more about the materials.
You can use an aluminum strip about 2.6 times thicker than your existing steel strip, and it will have nearly the same weight.
You can select from a high strength aluminum strip such as 7075-T6 to get the best strength that you can get. The resulting bending strength and bending stiffness will be somewhat like that of the steel (unspecified) that you used.
One thing that you can do is to experiment. Well, you'll have to do that anyway.
Do you have a metals supplier around for your business, or are you doing this in your garage?
Jim
Reply to
jbuch
I'm just doing this in my garage and it's for the base of a snowboard. My thinking is that a typical snowboard base of polyethylene offers very little in structure to the snowboard, so why not make the base metal. The best snowboards have a springy flex, so that's why I thought the hardened stainless steel ruler was a good example. The composition of the snowboard would be a sandwich construction with, starting at the bottom, the sheet metal base, a layer of fiberglass, a wood core, another layer of fiberglass, and finally a plastic top sheet. The only reason why I asked about aluminum was because the stainless steel was so much more expensive. I suppose I could use regular steel, but I'm worried about rusting. The base would get scratched, so I don't think I could use galvanized either. So I guess I'm looking for a springy, non-rusting, affordable sheet metal. I think I will take your advice and get some test strips of each and see if the aluminum at 2.6 times thicker has the similar qualities I'm looking for.
Reply to
Ken
Nobody makes springs out of aluminum. Metals used for springs include certain steel alloys, certain brass alloys, phosphor bronze, beryllium copper, certain titanium alloys. If you can't afford stainless, you probably can't afford anything except steel.
Any flat metal spring can be improved by shot peening.
As Uncle Al suggested, you're probably better off with a laminate. Always try to avoid asking one material to do two (or more) things, such as being a good spring material and being non-corrosive. A spring steel core surrounded by a fiber-reinforced plastic would be a good starting point.
I suggest you rethink whether you can tolerate holes. Holes in a steel core would allow you to control flex. For example, would it be useful to allow twisting flex? Holes along the central axis would provide additional twist compliance. It's not real obvious, but twisting puts tensile stress on the central axis.
Reply to
Mark Thorson
I like the idea of a composite. And the Liquid Metal and Quasicrystals look interesting. I'm going to try a aluminum base laminated to some carbon fiber to give it some spring qualities. I'd like to try one of the coatings on the aluminum base. Are the quasicrystal technologies available now, or are they still in the R&D stage? Does anyone know of companies that apply these coatings? I searched and found many articles, but no companies offering these services.
Reply to
Ken

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