Diffusion in the titanium-aluminum system. I. Interdiffusion between solid aluminum and titanium or titanium-aluminum alloys

Pure Ti as well as Ti—Al alloys have been coated in various ways with a pure solid Al layer and interdiffusion in the temperature range between 516 and 642°C has been investigated. In each case, a well adherent layer of TiAl3 is formed, growing according to a peculiar time-dependence. No other intermetallic compounds show up and no solid solution of Al in Ti arises. Two types of crystal structure of the TiAl3 layer have been found, depending on the temperature at which the layer was formed and on the composition of the starting alloy.