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

摘要

The atomic bonding of Al-Li alloy with minor Zr is calculated according to the “Empirical Electronic Theory in Solid”(EET).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 for Al3Li grain in alloy. Because there are the strongest covalent Al-Zr bond in Al3Zr and Al3(Zr, Li) particles, which is not easily sheared by dislocations, these covalent bonds can make a great resistant for dislocation moving, 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 united in between the interface of two phases. In this case, the intensity of atomic covalent bonding network in the whole alloy is much stronger than that in pure Al metal, and it gets the higher modulus.