| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 93 === The present study investigates the structural behavior of multi-elements alloy nanocluster in a defined temperature range between high and room temperature with the principles of molecular dynamics simulation. The applied potential parameter is the semi-empirical potential parameter of the tight-binding method. The fabrication parameter is analyzed by RDF, Wendt-Abraham parameter and pair analysis, including the effects of composition of alloy, additive elements, and quenching rate on the structure behavior of alloy nanocluster. The structural characteristic of the alloy nanocluster is directly influenced by the concentration of third additive. The increase in the third additive reduces its characteristics of element face centered cubic (FCC) (1421), but increases its characteristics of both icosahedron (1435, 1551, 1541) and body centered cubic (BCC). The increasing characteristic of BCC is the result of the formation of an intermetallic compound (CuNi)0.78Al0.22. Since the atomic radius of aluminum is larger than that of rhodium, the addition of aluminum led to a higher degree of lattice disruption than rhodium, and thereby renders the alloy nanocluster a higher degree of amorphous alloy formation (14.4 vs. 8%). The differences in the quenching rate of the alloys render the formation of amorphous and crystalline phases. The Wendt-Abraham parameter is then employed to determine the transition temperature of the alloy nanocluster. The limitation of the molecular dynamic simulation is also proposed in this study, and its improvement is an ongoing objective.
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