Be careful of fancy/exotic materials.
I spent $220 on a titanium light and it took me 6 weeks to realise that conventional aluminium is still the best.
I have a Jetbeam TC-R2.
The titanium has it's ups and downs.
The titanium styling is great - it makes flashlights like jewelry - it matches a Rado wrist watch.
However, it took six weeks to really sink in that this flashlight is not just a little heavier, but 1.5 times heavier.
Titanium is in fact 1.66 times heavier than steel.
It makes my fingers/wrist sore, esp holding it by the cigar with two fingers over technique.
Furthermore, the surface finish of titanium is not exactly the same as hard annodised aluminium.
Titanium has a glass/mirror-like polished surface that is smooth, and feels greasy and slippery in the hands.
When we hold by the tactical grip with four fingers over the top, and the thumb on the tail end switch, pressing a slightly stiff tail end switch makes the slippery titanium TC-R2 slide through the hand.
On the otherhand, conventional aluminium with HA finish is not coarse, but has a slightly "textured" finish.
This textured finish is not so slippery in the hand.
Finally, titanium feels hard and cold in the hand.
Aluminium feels softer, and warmer in the hand.
Titanium is in fact a much harder metal than aluminium.
Aluminium conducts heat some 15 to 20 times better than titanium, hence the quickly warmer feel, where Ti feels colder.
I haven't dropped my Ti on the ground at all so far.
My daily activities don't roughen the surface of the flashlight at all; for example, I don't carry my flashlight with keys, and I don't mix my flashlight in the same tool box with metal tools like hammers and screwdrivers etc.
However, I am led to believe that if I do drop my flashlight on the ground a lot, then Al will easily dent, while Ti is much more resistant to dents.
Also, mixing flashlights with keys and metal tools, will cause the surface annodising of Al flashlights to scratch easily, compared to a Ti light.
Thus for normal use, I prefer conventional aluminium.
For rugged use and beating around, then titanium is superior.
Therefore, if you would like to use tungsten carbide as a material for flashlights, just be careful - there's a lot of homework and testing to do...