Alexander Klimchouk, from Ukraine, has provided us with some incredibly well made titanium biners. While heavier than aluminum, they are somewhat lighter than steel and have excellent corrosion resistance. This alloy, as most titanium, is extremely tricky to work with. The U.S. aircraft industry went through years of growing pains, experiencing disasters after problems with intergranular corrosion and embrittlement. Don't try making these in your home laboratory.
Grain structure is uniform and surface finish is fine.
We pull-tested four of them, seeing fractures of the gate notch at an average of 6100 pounds. Far more interesting than the strength value was the fact that the observed standard deviation was 70 pounds. The tightly grouped failure values indicate close manufacturing controls and dimensional tolerances. While the makers get an A for manufacturing and processing, the design is a bit inefficient. They are, in fact, the theoretical titanium biners discussed above- round cross section, as thick as normal aluminum carabiners.