Metallurgy Commons^™

High Energy Synchrotron X-Ray Study Of Fatigue Damage In Amorphous And Polycrystalline Engineering Alloys, Chih-Pin Chuang

Doctoral Dissertations

The dissertation summarizes a series of studies on the fatigue damage of both amorphous and crystalline engineering alloys. The attention focuses on the utilization of synchrotron x-ray scattering related techniques for advanced material characterizations. In the first part of the research, critical issues regarding the mechanical response and structural evolution of Bulk-Metallic Glasses (BMGs) in the elastic region are addressed. The effects of cyclic-loading on the microstructures of an amorphous alloy are investigated, aiming to provide better mechanistic understandings of fatigue damage in BMGs. The second part of the research focuses on the characterization method based on two-dimensional X-ray diffraction …

Understanding Mechanical And Fatigue Behavior Of A Wrought Magnesium Alloy Using In-Situ Neutron And Synchrotron X-Ray Diffraction, Wei Wu

Doctoral Dissertations

Magnesium (Mg) alloys have received great attentions in the past several decades, due to their unique properties of low density, high strength-to-weight ratio, and high specific stiffness. Previous work on fatigue behavior of Mg alloys typically relies on ex situ microstructural characterization and crack-growth monitoring with replica techniques. The primary challenge is thus the lack of an in situ, non-destructive measurement on microstructural length scales, which prevents us from linking the stress analyses (top-down point of view) to the failure mechanisms on inter- and intra-granular scales (bottom-up point of view). A unique opportunity that resolves many of these difficulties …

Deformation Behavior Of Bulk Metallic Glasses And High Entropy Alloys By Nanoindentation, Yuting Li

Masters Theses

Nanoindentation has become a powerful tool in the measurement of the mechanical properties of diverse materials, such as metallic materials, polymer materials, and even biomaterials.

In this thesis, three types of Zr-based bulk metallic glasses (BMGs) were investigated by nanoindentation. Our work focuses on the characterization of the hardness, the reduced modulus, and the deformation behavior under different indentation conditions. The study of the hardness and the reduced modulus is to access the effect of the indentation load on deformation behavior and to determine the inhomogeneous deformation. The morphological profiles of the residual indentation on the surface of the specimen …