Can a metal be strong but have a low density?
Yes, both can be true. First, there is the ‘natural’ density of different metals. Titanium is lighter than steel, and can be made very strong. Iron can be cast in such a way that it is not very strong at all. And of course, lead, silver and gold – very dense metals – are especially weak. Then there is the way alloys are mixed: you can get a wide variation of strengths by using different proportions of different metals, carbon and so forth. Lastly, there is the shape and texture of the material. There have been honey-comb designs in steel that are almost as strong as solid steel, but less than 25% the weight. You might think that strong alloys must be much more expensive to make, but that is not always true. What makes strong metal more expensive is that it takes much stronger tools to work with stronger metals, and even these stronger more expensive tools wear out much faster.
