Jian Dong

Type

Text

Type

Thesis

Advisor

Trelewicz, Jason | Chen-Wiegart, Karen | Halada, Gary

Date

2017-01-01

Keywords

Materials Science

Language

en_US

Source

This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.

Identifier

http://hdl.handle.net/11401/78379

Publisher

The Graduate School, Stony Brook University: Stony Brook, NY.

Format

application/pdf

Abstract

Due to excellent physical and mechanical properties, such as high strength, high wear resistance and longer fatigue life, nanocrystalline alloys have attracted a good deal of attention in the field of material science. Based on this background, the thesis focuses on tungsten-copper binary alloy system, tungsten-zirconium binary alloy system, and tungsten-copper-zirconium ternary alloy system produced by high energy ball milling and analyzed by X-ray diffraction. Even though nanocrystalline metals are relatively unstable, doping solute into grain boundaries is a useful method to achieve stabilization. At low concentration, the doping solute can chemically mix with the base metal. As long as the concentration of doping solute increases to a limit value, the chemical mixed (segregate doped ions to grain boundaries) alloys will not be produced. In this work, it was found that, in W-Cu and W-Zr binary system, all samples were chemical mixing at low concentration (less than 10 at.% copper or zirconium), but the limit value is lower in W-Cu-Zr ternary system. Many mechanical properties of alloys are effected by the grain size and lattice parameter. Therefore, the grain sizes and lattice parameters are organized in this thesis work. | 63 pages

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