It was recalled that using L12-type Mn-containing Al3Ti alloys as coating materials was attractive because of their good room-temperature ductility and good oxidation resistance

at 1273K. Two kinds of diffusion couple, composed of L10 and L12 single-phase alloys with or without V, were used in diffusion experiments performed at 1273 to 1473K for 2.5 to 20h. During diffusion, L10 and L12 phases coexisted without any interphase, regardless of the diffusion temperature and V addition. Diffusion couples composed of alloys without V exhibited cracked regions at the interface between the L10 and L12 phases, while diffusion couples composed of the alloys with V exhibited no cracked regions. A L12-type alloy with V was shown to be an appropriate coating material for the L10 alloy.

Interface Stability in Diffusion Couple of L10 Type TiAl and L12 Type (Al,Mn)3Ti Alloys at 1273-1473K. G.Jin, T.Kimura, K.Gao, K.Hashimoto, L.Qiao: Materials Transactions, 2002, 43[10], 2600-3