9R phase enabled superior radiation stability of nanotwinned Cu alloys via in situ radiation at elevated temperature. (1st April 2019) - Fan, Cuncai
Abstract: Nanotwinned metals exhibit outstanding radiation tolerance as twin boundaries effectively engage, transport and eliminate radiation-induced defects. However, radiation-induced detwinning may reduce the radiation tolerance associated with twin boundaries, especially at elevated temperatures. Here we show, via in-situ Kr ion irradiation inside a transmission electron microscope, that 3 at. % Fe in epitaxial nanotwinned Cu (Cu97 Fe3 ) significantly improves the thermal and radiation stability of nanotwins during radiation up to 5 displacements-per-atom at 200 °C. Such enhanced stability of nanotwins is attributed to a diffuse 9R phase resulted from the dissociation of incoherent twin boundaries in nanotwinned Cu97 Fe3 . The mechanisms for the enhanced stability of twin boundaries in irradiated nanotwinned alloys are discussed. The stabilization of nano-twins opens up opportunity for the application of nanotwinned alloys for aggressive radiation environments. Graphical abstract: Image 1