Atomic states and brittleness of hcp Ti3Al-ordered-type alloys

On the basis of the framework of systematic science of alloys (SSA), the basic information such as states, volumes, and potential energies of characteristic atoms in hcp Ti-Al system have been determined. The average atomic state of the hcp Ti3Al compound consisting of ψ4Ti and ψ0Al atoms is 0.75[Ar](3dn)0.573(3dc)2.1685(4Sc)0.972(4sf)0.3093 + 0.25[Ne](3Sc)1.32(3pc)1.19(3Sf+3pf)0.49. The brittleness of the ordered hcp Ti3Al compound has been discussed considering the fundamental factors, which are atomic states, bond networks, potential energy wave planes, and the ratio XT/XAl. The existence of more pc and more dc directional electrons in the hcp Ti3Al compound lead to considerable brittleness; From bond networks and potential energy wave planes, the hcp Ti3Al compound has poorer ductility than the pure hcp Ti metal and the pure fcc Al metal: The Al-rich hcp Ti3Al ordered type alloys have poorer ductility than the Ti-rich hcp Ti3Al ordered type allows.