Evaluation of damage induced by high irradiation levels on alpha -Ni-Ni sub(3)Si eutectic structure

• Published in: Radiation effects and defects in solids 2015-06, Vol.170 (6), p.519-527
• Main Authors: Camacho Olguin, Carlos Alberto, Garcia-Borquez, Arturo, Gonzalez-Rodriguez, Carlos Alberto, Loran-Juanico, Jose Antonio, Cruz-Mejia, Hector
• Format: Article
• Language: English
• Subjects: Alloys; Damage; Eutectics; Intermetallic compounds; Intermetallic phases; Irradiation; Microstructure; Phases; Transmission electron microscopy
• ISSN: 1042-0150; 1029-4953
• DOI: 10.1080/10420150.2015.1052434

Diluted alloys of the binary system Ni-Si have been used as target of beam of ions, electrons, neutrons and so on because in this kind of alloy occurs transformations order-disorder, when the temperature is raised. This fact has permitted to evaluate the phenomena associated with the damage induced by irradiation (DII). The results of these works have been employed to understand the behavior under irradiation of complex alloys and to evaluate the reliability of the results of mathematical simulation of the evolution of the DII. The interest in the alloy system Ni-Si has been reborn due to the necessity of developing materials, which have better resistance against the corrosion on more aggressive environments such as those generated on the nuclear power plants or those that exist out of the Earth's atmosphere. Now, a growing interest to use concentrated alloys of this binary system on diverse fields of the materials science has been taking place because up to determined concentration of silicon, a regular eutectic is formed, and this fact opens the possibility to develop lamellar composite material by directional solidification. However, nowadays, there is a lack of fundamental knowledge about the behavior of this type of lamellar structure under aggressive environments, like those mentioned before. Hence, the task of this work is to evaluate the effect that has the irradiation over the microstructure of the concentrated alloy Ni22at%Si. The dendritic region of the hypereutectic alloy consists of an intermetallic phase Ni sub(3)Si, whereas the interdendritic region is formed by the alternation of lamellas of solid solution alpha -Ni and intermetallic phase Ni sub(3)Si. Such kind of microstructure has the advantage to get information of the DII over different phases individually, and at the same time, about of the microstructure influence over the global damage in the alloy. The hypereutectic Ni22at%Si alloy was irradiated perpendicularly to its surface, with 3.66MeV - Ni ions up to 380dpa at 650 degree C in a Tandetron linear accelerator. The level of irradiation dose was chosen similar to the irradiation conditions of the next-generation nuclear reactors. The theoretical maximum depth of the DII (maximum depth of damage (MDD)) was calculated as 1.35 mu m using the SRIM-2013 program; the laminar microstructure of the eutectic was simulated using the lattice parameters of the eutectic before irradiation. The experimental MDD was 1.47 mu m, as determined thro