"exactly the same material" is correct and usable in written English.
You can use it when referring to something that is the same in composition or content. For example, "The dress was made from exactly the same material as the one I bought last year."
It's Italian white marble, exactly the same material as I would use for the sculptures.
In a characteristically contrary move, he made his two back-to-back Sound Museum albums with this group – the sessions featuring the same band on almost exactly the same material, in a challenge to listeners to detect and savour minuscule differences.
The other is a custom-fitted shirt from men's clothier startup J. Hilburn made from exactly the same material, but it only costs $99.
A material in a biological structure, such as a bone or plant stem, experiences stresses which are higher than would be allowed in an engineering structure, even if we were using exactly the same material.
Some of the interobserver variations appear simply due to technicalities: not reviewing exactly the same material may result in a different diagnosis because of sample differences.
This remarkable increase of more than 100 mV in the Voc (14%) using exactly the same material arises only through careful engineering of the nanophotonic resonances.
The officials typically decree that roofs are repaired with exactly the same materials as before.
The bombers who attacked London's public-transportation system in 2005, Clarke pointed out, "used exactly the same materials".
So, he says, it's interesting that at least some of the votives were treated with "exactly the same materials that were being used with humans".
However, the results of peel tests were not conclusive because the unexposed specimens of this series were fabricated much later (in 2006) than 1992 and could not be made from exactly the same materials used in 1992.
Here, while comparing the in vitro translocation to in vivo data, we noticed that very few studies tested exactly the same materials in both settings.
