Depends on how good of a chemist your time traveler is. While the purification methods on many of the needed materials were not discovered until the 1900s a good chemist, craftsman, and historian could go back further to the discovery of the ores he needs.
To make the alloy you will need Iron, Titanium, Vanadium, and Aluminum:
Iron has been around for ~5000 years; so, this is the easy one.
Titanium ore was first discovered in 1791 and could be purified via the Hunter process using chemicals that would be available by 1808 when Sir Humphry Davy learned to isolate pure calcium.
Vanadinite, discovered in 1801 could also be purified by 1808 due to Sir Humphry Davy's discovery.
Bauxite was discovered in 1821. All of the materials you would need for the Bayer process required to turn it into alumina already existed. The Hall-Héroult process required to turn alumina into aluminum requires strong electrical currents, but if you have a time machine, I suspect you've also got one hell of a power source your could tap into to pull electricity from.
[EDIT]
He can set his arrival anywhere on Earth. He also has no diplomatic or monetary problems. He can mine the resources or has the raw ores in storage.
Not sure if I just missed this before or if the question was revised. If the ore is not a problem, then all you are left needing are a good smelting facility and hydrochloric acid
Hydrocloric Acid has been manufactured since about 800AD. It is made from Iron (II) sulfate (which was first used as an ink pigment sometime around 600BCE) and rock salt (which has been used since about 6000BCE). When you consider that these are both commonly minable substances, that means you could just add this to your grocery list of ores. There is also a good chance your timeship will have some extra batteries you could extract it from to save you some time if you are not needing a lot of titanium.
This really just leaves the smelting furnace as your only big obstacle. Simple furnaces that you could probably make by hand and fuel with easily obtainable natural resources can only reach ~1300C, but you would not be able to get your iron pure enough with one. Finery forges are capable of fully melting iron allowing full separation of iron and slag, and could reach the temperatures required to process all of the materials needed to make your small amounts of your titanium alloy. These were first made sometime between 400-200BCE in ancient China. All ancient depictions I've seen of finery forges are pretty large; so, this may be the one thing you really need an existing civilization to be able to acquire.
Incidentally, China is also rich in all of the ores that you need; so, you don't need to go very far for any of your materials.
So, you could in theory go to China (~200BCE), find someone with a finery forge, and offer to exchange some modern metallurgy know how in exchange for use of their equipment.