> oxidation at high temperatures
SLM machines typically use an Argon gas chamber. DED machines use an Argon gas shield.
> It’s more typical to print copper alloys than pure copper.
In the context of modern SLM, it depends on your definition of "pure" and "alloy". During the process, a bit of resin to is mixed into the powder and heat treated in a final step to get to 99.9% pure copper.
edit: Just fixed up my knowledge. Indeed alloys are typically used (99% copper with things like Chrome added on depending on use-case), tough the pure copper can be used with higher laser power.
I think there’s still quite active research in the area, though, and no doubt there’s a lot going on that I don’t know! https://www.sciencedirect.com/science/article/pii/S026412752...
The copper use-case is what kick-ed off an industry-wide race towards offering blue laser as an option. There is more than just wavelength that goes into printing good copper results, but that is a major factor.