Amorphization and nanocrystallization of Ni-Nb-Si Alloys

New Ni-Nb-Si amorphous alloys with enhanced thermal stability and toughness were developed, and the effect of Si on the amorphization, nanocrystallization, and mechanical properties of these alloys were examined. The mechanical properties and thermal stability of Ni60Nb40, Ni57.5Nb37.5Si5, and Ni55Nb35Si10 amorphous alloys were improved as the Si content was increased. Nanocrystallization of the Ni55Nb35Si10 amorphous alloy led to the formation of intermetallic crystals with sizes below 10 nm in the amorphous matrix. Formation of Nb7Ni6, NbNi3, and Nb3Ni2Si nano-crystalline phases significantly increased the hardness and the elastic modulus of amorphous/nano-crystalline alloys. The toughness of the alloys were observed to increase with the addition of Si in the amorphous and amorphous/nano-crystalline state.