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Hfco2 Laves Phase Intermetallics - Part Ii: Elastic And Mechanical Properties As A Function Of Composition, Katherine C. Chen, Fuming Chu, Paul G. Kotula, Dan Thoma
Hfco2 Laves Phase Intermetallics - Part Ii: Elastic And Mechanical Properties As A Function Of Composition, Katherine C. Chen, Fuming Chu, Paul G. Kotula, Dan Thoma
Materials Engineering
In efforts to establish and understand structure–property relationships in Laves phase intermetallics, elastic and mechanical properties are studied as a function of composition in the C15 HfCo2 system. Elastic constants and Debye temperatures are determined by resonant ultrasound spectroscopy (RUS) at room temperature. A maximum near the stoichiometric Laves composition is revealed with the Young's modulus, bulk modulus, and Poisson's ratio. In addition, a slight drop in shear modulus is found with Co-rich compositions, and the Debye temperature increases with Co-content. Room temperature Vickers indentation is performed to assess the microhardness and fracture toughness of the HfCo2 alloys. …
Hfco2 Laves Phas Intermetallics - Part I: Solubility Limits And Defect Mechanisms, Katherine C. Chen, Eric J. Peterson, Dan J. Thoma
Hfco2 Laves Phas Intermetallics - Part I: Solubility Limits And Defect Mechanisms, Katherine C. Chen, Eric J. Peterson, Dan J. Thoma
Materials Engineering
Solubility limits and constitutional defects in Laves phase intermetallics are investigated with the C15 HfCo2 system. Several binary alloy compositions based on HfCo2 are characterized by optical and scanning electron microscopy (SEM), electron microprobe analysis (EPMA), X-ray diffraction (XRD), and density measurements. Rietveld refinements of XRD scans are used to determine lattice constants, anisotropic strain parameters, and atomic occupancies. Compositional trends are compared against predicted or calculated trends due to an anti-site substitution or vacancy defect mechanism. Geometric models and atomic size factors are used to establish solubility limits and to give insight into defect mechanisms. Results from …