In situ TEM observations of unusual nanocrystallization in a Ti-based bulk metallic glass

In situ transmission electron microscopy (TEM) has been used to witness the nanocrystallization of amorphous Ti42.5Cu40Zr10Ni5Sn2.5. A crystallization front exists to separate the TEM sample into two parts with different thermal stabilities. The number density of the crystallization products varies significantly, with the precipitate sizes ranging from a few nanometres to ∼100 nm. Detailed TEM analysis suggests that oxygen is the most likely reason for realizing the unusual nanocrystallization. External thermal analysis also indicates that oxygen affects the crystallization.