Consolidation of Al-TiO₂ and Ti₃Al-Ai₂O₃ composite powders
type: CreativeWork
description: Pressureless sintering, hot pressing and sinter-HIP of Ti₃Al-Al₂O₃ and Al-TiO₂ composite powders have been carried out under inert atmospheres. The Al-TiO₂ composite powders were produced by discus milling Al/TiO₂ powder mixtures followed by ball milling. The Ti₃Al-Al₂O₃ composite powders were produced by heating Al/TiO₂ powder mixtures. Densification, sintering behaviour, microstructural development and mechanical properties of the composites were investigated for the variables of pressure and temperature at different powder particle sizes. It was shown that higher bulk density and lower porosity were obtained by hot pressing compared to pressureless sintering. A temperature of 1600°C is required to achieve >95% theoretical density of the composites when fabricated by pressureless sintering Ti₃Al-Al₂O₃ composite powder. However, fully densified composites could be fabricated by hot pressing l.2μm Ti₃Al-Al₂O₃ composite powder at 1474°C under vacuum for a one hour holding period. The growth of Al₂O₃ particle size and the development of microcracks at the Ti₃Al-Al₂O₃ interfaces were evident with the increasing temperature above 1500°C for the composites produced by pressureless sintering and hot pressing. Near fully densified Ti₃Al-TiO-Al₂O₃ and Ti₃Al-Al₂O₃ composites (96% of theoretical density) with ≤4μm Al₂O₃ particle size in the composites could be achieved by pressureless sintering Al-TiO₂ composite powder at 1480°C in argon for 4-5 hours of holding period. Fully dense Ti₃Al-Al₂O₃ composite microstructures could be achieved by hot pressing four hours discus milled composite powder subjected to 24 hours of ball milling giving a starting median particle diameter of 7μm, at 1387°C under vacuum. The XRD traces show that the Ti₃Al phase in the Ti₃Al-Al₂O₃ composites is maintained above 50% XRD peak intensity up to 1500°C. The composite microstructure demonstrates that both the Al₂O₃ and Ti₃Al phases are continuous and exhibit an interpenetrating network. Near fully de…
abstract: Pressureless sintering, hot pressing and sinter-HIP of Ti₃Al-Al₂O₃ and Al-TiO₂ composite powders have been carried out under inert atmospheres. The Al-TiO₂ composite powders were produced by discus milling Al/TiO₂ powder mixtures followed by ball milling. The Ti₃Al-Al₂O₃ composite powders were produced by heating Al/TiO₂ powder mixtures. Densification, sintering behaviour, microstructural development and mechanical properties of the composites were investigated for the variables of pressure and temperature at different powder particle sizes. It was shown that higher bulk density and lower porosity were obtained by hot pressing compared to pressureless sintering. A temperature of 1600°C is required to achieve >95% theoretical density of the composites when fabricated by pressureless sintering Ti₃Al-Al₂O₃ composite powder. However, fully densified composites could be fabricated by hot pressing l.2μm Ti₃Al-Al₂O₃ composite powder at 1474°C under vacuum for a one hour holding period. The growth of Al₂O₃ particle size and the development of microcracks at the Ti₃Al-Al₂O₃ interfaces were evident with the increasing temperature above 1500°C for the composites produced by pressureless sintering and hot pressing. Near fully densified Ti₃Al-TiO-Al₂O₃ and Ti₃Al-Al₂O₃ composites (96% of theoretical density) with ≤4μm Al₂O₃ particle size in the composites could be achieved by pressureless sintering Al-TiO₂ composite powder at 1480°C in argon for 4-5 hours of holding period. Fully dense Ti₃Al-Al₂O₃ composite microstructures could be achieved by hot pressing four hours discus milled composite powder subjected to 24 hours of ball milling giving a starting median particle diameter of 7μm, at 1387°C under vacuum. The XRD traces show that the Ti₃Al phase in the Ti₃Al-Al₂O₃ composites is maintained above 50% XRD peak intensity up to 1500°C. The composite microstructure demonstrates that both the Al₂O₃ and Ti₃Al phases are continuous and exhibit an interpenetrating network. Near fully de…
author: Han, Ching Zen
license: https://researchcommons.waikato.ac.nz/bitstreams/b83b2105-d3ce-4063-8591-4f82745d6311/download
date published: 2005
date modified: 2026-07-24T05:57:46Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato