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I am looking for non-destructible way which can be performed in home conditions to tell if the material is titanium (in my case it is a mug). Advices like "grind it" or "use electronic microscope" could be useful but I cannot apply them as stated above. I am targeting primarily aluminium and steel alloy because of their competitive prices and availability. In pure form detection would be easy (weight) but what about the alloy?

I am also asking for non-expert level ways -- I can weight something, boil water, measure temperature or resistance, those kinds of stuff. I am not a chemist for sure.

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    $\begingroup$ "What about the alloy" - the specific gravity of pure titanium is about 4.5 compared with 8.0 for steel. Common titanium alloys are at least 90% titanium and much of the remainder is "light" elements like aluminium, so there should be no problem distinguishing titanium alloy from steel by density. Aluminium has s.g. 2.7 so aluminium alloys should be distinguishable as well, being less dense than pure titanium. $\endgroup$
    – alephzero
    May 1, 2019 at 11:14
  • $\begingroup$ The easiest way to tell them apart is just to look at them, but you need some known samples of items made from titanium to learn what its colour and surface finish looks like. $\endgroup$
    – alephzero
    May 1, 2019 at 11:21
  • $\begingroup$ @alephzero, I was not clear, but alloy here I meant mixture of aluminium and steel to mock titanium for weight. $\endgroup$
    – greenoldman
    May 1, 2019 at 18:12

2 Answers 2

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Do what Archimedes did in the 3rd century BCE, when the king asked him to find a nondestructive way to ascertain whether this crown was made of pure gold, as request, or whether it was made of gold alloy.

Accurately find the mass of the object and also accurately find its volume. Divide the mass by the volume to obtain the density of the object and compare that to published values of density for the material the object is supposedly made from.

An accurate set of scales will give you the mass and by collecting all the water displaced by placing the object in a container of water and accurately measuring the volume using a finely graduated measuring cylinder will give you the volume you need.

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    $\begingroup$ You can also measure water spillage with scales quite accurately. In fact identifying material of 3 random shaped samples with just a scale was the introductory lab assignment in our uni physics lab. $\endgroup$
    – joojaa
    May 1, 2019 at 14:22
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In adition to measuring the density of your object as described by Fred there is a few other tests you can easily make. You can try to measure:

  • Heat capacity of your object. By heating the object in hot water measure tempertaure. Then move it over to another cooler water container where you know the volume and measure the temperture of the water after this.Then compare to table values

  • Specific electrical resistance is also very quick to do if you happen to have a multimeter. This would very quickly rule out aluminium. Requires very minimal setup time to do this measurement.

Now density is best but adding these to the mix can give you a better confidence in your results. Resistance measurement also works if you suspect there is a hollow cavity in your object.

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    $\begingroup$ Surface films (anodizing etc) may introduce an insulating film on the part and could make resistance measurements of the metal uncertain. $\endgroup$
    – D Duck
    May 1, 2019 at 22:24
  • $\begingroup$ @DDuck That is true. $\endgroup$
    – joojaa
    May 2, 2019 at 4:01

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