I wonder if you could do this with similar metal alloys to get an ingot that changes physical properties along its length - for example, a bar that's harder on one end but more elastic on the other.

Look up additive manufacturing of gradient alloys. Lots of people are trying to do things like print one end as a titanium alloy and transition to stainless steel in the same build.

One of the practical problems with this is galvanic corrosion between the distinct metals.

That sounds similar to Powder Metallurgy[1] which we use to make otherwise impossible alloys possible.

1: https://en.wikipedia.org/wiki/Powder_metallurgy

You may be interested in how jet turbine blades are made: https://news.ycombinator.com/item?id=12474148

That process seems a bit subtler, since it's more about conditions than composition, but the end result is varying properties along the turbine.

The Ripple coffee art printer better watch out, scientists are getting closer to 3D printing the “perfect” latte. ;)

I thought this was gonna be some article describing a new latte they made

Has science gone too far

Sometimes i read a paper and wonder if the authors are actually gunning for an Ignobel nomination. I prefer serendipitous nominations, I think.

This brings to mind Einstein's paper on meanders in rivers, in which he builds a solution from the behavior of tea leaves swirling in a teacup.

I don't think we should discard the value of the work based solely on the quotidian nature of the examples. (That said, I don't know enough about fluid dynamics to judge whether there's something novel going on in the paper, or if it's just people being clever.)

https://books.google.com/books?id=9fJkBqwDD3sC&pg=PA249&lpg=...

Eh, a physicist friend of mine working on his PhD noticed something interesting in his tea during a tea break with his labmates and they went and researched it. Had the result turned out more interesting they might have published, and maybe being nominated for an Ignobel. It's not about gunning for, it's about curious people researching whatever they happen to touch, which is usually a cup of hot beverage.