Atomic bonding and mechanical properties of Al–Li–Zr alloy

The atomic bonding of Al–Li alloy with minor Zr is calculated according to the “Empirical Electronic Theory in Solids”. The result shows that the stronger interaction between Al and Zr atoms, which leads to form the Al–Zr segregation regions, promotes the precipitation of Al3Zr particles and produces a remarkable refinement of Al3Li grains in the alloy. Because there are the strongest covalent Al–Zr bonds in Al3Zr and Al3(Zr, Li) particles, these covalent bonds can cause a great resistance for dislocation movement, and is favorable to strengthen the alloy. On the other hand, with precipitating the Al3(Zr, Li) particles, it causes the coherent interphase boundary energy of Al/Al3Li to decrease, and atomic bonding is well matched in between the interface of two phases.