Abstract

Amorphous alloys are used as structural materials due to their ability to have unusual and attractive combinations of physical and mechanical properties. However, it is extremely difficult to obtain the bulk amorphous alloy in traditional method, for example, casting and solidification. In this work, we use the solid state amorphization reaction (SSAR) process in amorphization of multilayer thin films according to interdiffusion. When mechanical alloying (MA) is conducted on an alloy system where the SSAR criteria are met, amorphization due to the SSAR mechanism can occur. The fine, lamella morphologies produced during MA of elemental crystalline precursors creates a layered structure that is geometrically similar in shape and scale to the thin film forms used in SSAR. Therefore amorphization take place at the clean interfaces between the elements during balling milling and subsequent annealing heat treatment.
The lamella structure of binary alloy of Zr-Ni system was produced by mechanical alloying of elemental crystalline powders at intermediate time. Amorphous metallic alloys were synthesized in solid state amorphization reaction between alternate lamella structures during mechanical alloying process and subsequent annealing heat treatment. The evolution of lamella microstructure is illustrated by Scanning electron microscopy. X-ray diffraction, differential scanning calorimetry were used to assess the amorphous state. Further annealing results in the intermetallic alloy at elevated temperature eventually.

 

Biography

Kai Zhang received his M.S. degree in center for materials research from Norfolk State University in 2005. He is currently pursuing his Ph.D. under the direction of Dr. Alex Aning. His area of study is the synthesis of bulk amorphous Zr-Ni binary Alloy by mechanical alloying and annealing.