I’m not sure that wearing around an inch and a quarter thick plate of titanium is an improvement over the thinner steel (based on bulkiness), but it sure does stop the rounds, even a black tip .50BMG (which almost made it through). I imagine that the energy transfer through the plate would still be enough (on the larger calibers) to result in you having a pretty bad day.
Experimenting with different materials for use in armor is interesting, and having worn both ceramics and steel before, they both have their advantages and disadvantages. Personally, the reduced bulk of steel along with its greater durability was the deciding factor for me–I think it is easier to get away with carrying some extra weight in a plate carrier for the types of operations that would require such equipment.
Based on some basic googling it looks like there are some solutions out there that are not horribly expensive ($130 for a 10″x12″ plate at Security Pro USA; they were just the first to come up in my search; featured image is from their page) with an unbelievable 4.5mm thickness (for stopping 7.62x39mm rounds).
So, readers, thoughts? My understanding is that titanium is more brittle than steel, so presumably a thinner plate would be more prone to breakage than did the inch and a quarter plate that was tested in this video. Not being a metallurgist, would anyone venture a guess as to an alloy that would generally retain the strength and weight of titanium, but reduce the brittleness (i.e. how many rounds would the above 10″x12″ plate potentially withstand)? Would it be worth the cost?