The possibilities to lower the stacking fault energies of aluminum materials investigated by first-principles energy calculations

The stacking fault energies (SFEs) of various aluminum solid solutions were investigated against temperature and solute concentration using first-principles energy calculations. Three types of impurities, including intrinsic defects, substitutional solute atoms and interstitial solutes were considered to study their effects on the SFEs in corresponding aluminum solid solutions. It is shown that the intrinsic defects hardly change the SFEs of aluminum, whereas substitutional solutes such as Ge, Y, Sc, Sr and interstitial solutes such as C, N, H, can drastically lower the SFEs of aluminum at low temperatures. Our study suggests that at circumstances the possibilities to introduce twins in aluminum materials can be increased significantly, since their SFEs can be lowered to the values smaller than 45 mJ/m(2). The physical mechanism of lowering the SFEs in those aluminum solid solutions were interpreted by their electronic structures around the SFs and the solutes or impurities. (C) 2015 Elsevier B.V. All rights reserved.