Heat treatments involved with pure titanium are stress relieving and annealing.

Alpha alloys are generally not heat treated.

Beta alloys respond well to hardening type heat treating, since they have a higher density than pure titanium. Quenching titanium from the beta-phase yields a martensitic transformation and improved strength.

Alpha-beta phase alloy heat treatments include annealing, solution treatment, and stress relieving.

When heat treating titanium, furnaces running argon gas are common, as well as vacuum furnaces. Fasteners, for example, are typically run in argon atmosphere shaker hearth furnaces. Tight temperature control (±10°F) is required. Compared to other materials, titanium alloys have relatively low processing temperatures. Titanium alloys have a service capability of 350°F to 1000°F.

Titanium alloys are particularly useful in the aerospace and medical industries. A good strength to weight ratio, low density, low coefficient of thermal expansion, good corrosion resistance, good oxidation resistance at intermediate temperatures, and good toughness combine to make titanium alloys an excellent material for the aerospace and defense industries. The medical industry typically sees titanium in the use of orthopedic and orthodontic implants.

Source: Dan Herring, The Heat Treat Doctor®, Atmosphere Heat Treatment, Volume 1, pages 549–556.