The origin of exceptionally large ductility in molybdenum alloys dispersed with irregular-shaped La ₂O ₃ nano-particles

Abstract

Molybdenum and its alloys are known for their superior strength among body-centered cubic materials. However, their widespread application is hindered by a significant decrease in ductility at lower temperatures. In this study, we demonstrate the achievement of exceptional ductility in a Mo alloy containing rare-earth La ₂O ₃ nanoparticles through rotary-swaging, a rarity in Mo-based materials. Our analysis reveals that the large ductility originates from substantial variations in the electronic density of states, a characteristic intrinsic to rare-earth elements. This characteristic can accelerate the generation of oxygen vacancies, facilitating the amorphization of the oxide-matrix interface. This process promotes vacancy absorption and modification of dislocation configurations. Furthermore, by inducing irregular shapes in the La ₂O ₃ nanoparticles through rotary-swaging, incoming dislocations interact with them, creating multiple dislocation sources near the interface. These dislocation sources act as potent initiators at even reduced temperatures, fostering diverse dislocation types and intricate networks, ultimately enhancing dislocation plasticity.

Abstract

Application of Molybdenum alloys is hindered by reduced ductility at lower temperatures. Here, the author shows improved ductility in a Mo alloy with irregular-shaped rare-earth La ₂O ₃ nanoparticles achieved via rotary-swaging, attributed to the amorphization of the oxide-matrix interface.