Of Ni3al Nano-materials On Thermodynamic Properties Of Molecular Dynamics Simulations

Low-dimensional nanostructures have attracted intensive research owing to their novel physical, chemical, and electro-optical properties as well as their potential applications in nanodevices. It is worthy of study not only for understanding the fundamental physical phenomena, but also for their promising applications such as functional building blocks for novel electrical, optical and magnetic nanodevices. In this dissertation the physical properties, such as thermal stability, thermal conductivity, mechanical and electrical properties, of Ni3Al one, two dimensional nanostructures and bulk are investigated using classic molecular dynamics with a Finnis-Sinclair potential.1. Molecular dynamics method is used to investigate the thermal stability, thermal conductivity of single Ni3Al nanowires and nanofilms. The results are listed as follows:The melting temperature of Ni3Al nanowires and nanofilms increases with the size (the diameter of nanowires and the thickness of nanofilms) to a saturation value, which is close to the melting temperature of bulk Ni3Al. The melting of the [001]-oriented nanowires and nanofilms whose cross sections formed by the square shape starts from the surface, and rapidly extends to the inner regions as the temperature increases. The large surface-to-volume ratio of the nanowires and nanofilms may account for the decreased melting temperature observed in the present simulations.2. Using the classical molecular dynamics methods, the nanomechanical behavior of the [001]-oriented nanowires whose are studied with the purpose to identify the mechanism of failure under tensile and compressive strain. The results are listed as follows:The elastic limit of the nanowire is up to about 15% strain with the yield stress of 5.99-6.48 GPa under tensile strain. At the elastic stage, the deformation is carried mainly through the uniform elongation of the bond between atoms. With further strain, the slips in the {111} planes occur to accommodate the applied strain at room temperature under tensile strain, while the nanowires accommodate the compressive strain by the formation of twins within the nanowires. This outcome is in agreement with the Euler theory.