A study of phase stability and mechanical properties of hydroxylapatite-nanosize alpha-alumina composites

Date

2007-04-01

Author

Evis, Zafer

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

273
views

0
downloads

Hydroxylapatite (HA)-nanosize alumina composites were synthesized to study their phase stability and mechanical properties. To make these composites, nanosize alpha-Al2O3 powder was used because of its better sinterability and densification as compared to nanosize gamma-Al2O3. The composites were air sintered without pressure and hot pressed in vacuum at 1100 degrees C and 1200 degrees C. In the composites, HA decomposed to tricalcium phosphate faster after the air sintering than hot pressing. Moreover, hexagonal unit cell volume of HA left in the composites showed that there was more decomposition of HA after the air sintering than hot pressing. It also showed that HA in the composites was OH- and Ca2+ deficient. As the amount of alumina increased, sinterability considerably decreased. Hot pressing at 1200 degrees C resulted in better mechanical properties (mu-hardness and fracture toughness) than the hot pressing at 1100 degrees C.

Subject Keywords

Mechanical Engineering, General Materials Science, Mechanics of Materials, Condensed Matter Physics

URI

https://hdl.handle.net/11511/39787

Journal

MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS

DOI

https://doi.org/10.1016/j.msec.2006.05.028

Collections

Department of Engineering Sciences, Article

Suggestions

OpenMETU
Core

The role of amorphous precursor in phase selection hierarchy in marginal metallic glasses YILDIRIM, CİHAN; KUTSAL, M.; OTT, R. T.; BESSER, M. F.; KRAMER, M. J.; Kalay, Yunus Eren (Elsevier BV, 2016-12-15) The solid state amorphous structure and devitrification products of Al90Tb10 alloys produced by Cu block meltspinning and magnetron sputtering were investigated by a combined study of differential scanning calorimetry, in-situ X-ray diffraction and conventional transmission electron microscopy. The as-prepared specimens were found to be fully amorphous according to the electron and X-ray diffraction. The thermal analysis and in-situ XRD analyses of the amorphous samples having the same chemistry but differe...
In-situ observation of nano-oxide and defect evolution in 14YWT alloys Aydoğan Güngör, Eda; Li, M.; Maloy, S.A. (Elsevier BV, 2020-12-01) © 2020 Elsevier Inc.Nanostructured ferritic alloys (NFAs) are considered as candidates for structural components in advanced nuclear reactors due to their excellent radiation resistance as a result of a high density of nano-oxides (NOs) in the microstructure. Therefore, gaining an understanding on the stability of NOs under irradiation is crucial. In this study, we have investigated the evolution of defects and NOs in 14YWT NFAs under in-situ Kr ion irradiation at room temperature (RT) and 450 °C up to 10 d...
Investigating the effects of hardening of aluminium alloys on equal-channel angular pressing-A finite-element study Karpuz, P.; Simsir, C.; Gür, Cemil Hakan (Elsevier BV, 2009-03-15) Equal-channel angular pressing (ECAP) is a promising severe plastic deformation method for production of ultrafine-grained bulk metals and alloys with considerably improved mechanical properties. In this study, numerical experiments were carried out to investigate the effect of strain hardening of aluminum alloys on the process performance of ECAP via finite element modeling. In the constitutive model, isothermal-plane strain, frictionless condition was assumed. The numerical results showed that strain hard...
Improvement of fracture resistance in a glass matrix optomechanical composite by minicomposite unit bridging Dericioğlu, Arcan Fehmi (Elsevier BV, 2005-10-15) Minicomposite unit bridging, which was experimentally determined to be the dominant toughening mechanism resulting in the R-curve behavior of the Al2O3-ZrO2 minicomposite-reinforced glass matrix optomechanical composite, was studied quantitatively using luminescence spectroscopy. Applied stress induced shift of the luminescence bands of the minicomposite reinforcement was calibrated. Using the experimentally obtained calibration curve, axial stresses could be mapped along the minicomposite embedded in the g...
Effect of Microstructure on the Mechanical Behavior of Reactive Magnetron Sputtered Al2O3/TiO2 Multilayer Ceramics Dericioğlu, Arcan Fehmi (Japan Institute of Metals, 2008-11-01) Mechanical characteristics of reactive magnetron sputtered Al2O3-TiO2 multilayer ceramics were studied. Tailored mechanical properties such as moderately high hardness and reasonable toughness were achieved through varying sputtering process parameters resulting in microstructural control at nano-scale. Interchanging Al2O3 and TiO2 layers with a single layer thickness of similar to 65-70 nm were deposited on single crystal alumina (sapphire) substrates to form the multilayer structure composed of 10 layers....

Citation Formats

Z. Evis, “A study of phase stability and mechanical properties of hydroxylapatite-nanosize alpha-alumina composites,” MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS, pp. 421–425, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39787.