Stable element in Ti6Al4V in alpha phase is?
V
Al
Ti
Al, V
Alpha titanium wires are manufactured from grade V titanium alloy containing 6% aluminum and 4% vanadium. These wires have good formability and stiffness equal to that of stainless steel. These wires possess poor spring back, and hence their use in orthodontics is limited for applying torque at the finishing stage. Aluminum is used to stabilize the alloy in alpha phase.
GRADE V TITANIUM ALLOY (Ti6Al4V, OR Ti6-4) 
6% Aluminum
4% Vanadium
0.25% Iron
0.2% Oxygen 
Textbook of ORTHODONTICS Sridhar Premkumar