Eur. Phys. J. B (2018) 91: 239
https://doi.org/10.1140/epjb/e2018-90274-6

Regular Article

Cu segregation at α-Al (1 1 1)/δ^′-Al₃Li (1 1 1) interface

¹ College of Engineering, Yantai Nanshan University, Yantai 265713, P.R. China
² Materials School, Central South University, Changsha 410083, P.R. China
³ Key Lab of Nonferrous Materials of Ministry of Education, Central South University, Changsha 410083, P.R. China

^a e-mail: yjg0323@126.com
^b e-mail: dengfeng@csu.edu.cn

Received: 23 April 2018
Received in final form: 30 June 2018
Published online: 8 October 2018

Abstract

Segregation behaviors of Cu at α-Al (1 1 1) (1 1 1)/ δ^′-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 α-Al (1 1 1)/δ^′-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 α-Al (1 1 1)/δ^′-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.