Paper stronger than cast iron
What do you do if you are a scientist in Sweden and can’t get any cast iron to build your steam engine out of? You invent some paper that is stronger than cast iron of course.
By bashing their wood pulp and treating it with enzymes, Lars Berglund and colleagues made fibres 1000 times smaller than regular paper fibres. These were coated using carboxymethanol and the result was a material with over double the tensile strength of cast iron. The machining properties and vulnerability to steam of this new material are not described so perhaps my suggestion of building steam engines is not yet viable?