Cu segregation at alpha-Al (111)/delta '-Al3Li (111) interface

摘要

Segregation behaviors of Cu at alpha-Al (1 1 1) (1 1 1)delta'-Al3Li (1 1 1) interface were investigated with the first-principle pseudopotential plane-wave method. The results show that the most stable atomic coordination relations for alpha-Al (1 1 1)/delta'-Al3Li (1 1 1) interface is the structure of which the ABC stacking order of FCC lattice along (1 1 1) direction is kept at both two interfaces of Al and Al3Li phases. At 1/4 ML coverage, Cu atom is inclined to be segregated at alpha-Al (1 1 1)/delta'-Al3Li (1 1 1) interface by adopting the interstitial rather than the substitution mode. The favorite interstitial site is the position where Cu atom is surrounded by three symmetrical Al atoms. Based on the calculation of separation work, we predicted that interstitial Cu can effectively improve the strength of the whole interface region, especially the area inside Al matrix, this is in agreement with the experimental results.