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Kumar, Vishank
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Effect of SPS Process Parameters on the Densification Behaviour of Yttria Stabilized Zirconia

SAE International Journal of Materials and Manufacturing

University of British Columbia-Abhinav Karanam, Vishank Kumar, Lukas Bichler
  • Journal Article
  • 2014-01-0835
Published 2014-04-01 by SAE International in United States
Zirconium dioxide (ZrO2) doped with Yttria exhibits superplastic behaviour, corrosion resistance and excellent ion conducting properties [1] at moderate temperatures and thus it can be used as an electroceramic to measure the pH of high temperature water used in fuel cells. Several fabrication processes are available for preparation of zirconia ceramics. This research focused on the study of using Spark Plasma Sintering (SPS) process to prepare Yttria Stabilized Zirconia (YSZ) ceramic.8 mol% YSZ was subjected to varying SPS sintering conditions. Samples were sintered by changing the heating cycle, dwell time, sintering pressure and cooling cycle. Subsequently, these parameters were related to the densification characteristics of the as-sintered YSZ. The results of specific gravity measurements and microstructure evaluation suggest that stepped heating followed by a slow cooling results in YSZ with highest relative density (99.9%).
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Effect of Chill Parameters on the Residual Strain in Cast 319 Aluminum Alloy: A Neutron Diffraction Study

SAE International Journal of Materials and Manufacturing

National Research Council Canada-Dimitry Sediako
University of British Columbia-Vishank Kumar, Lukas Bichler
  • Journal Article
  • 2014-01-0836
Published 2014-04-01 by SAE International in United States
The demand for light weight vehicles continues to stimulate extensive research into the development of light weight casting alloys and optimization of their manufacturing processes. Of primary relevance are Aluminum (Al) and Magnesium (Mg) based alloys, which have successfully replaced selected iron based castings in automobiles. However, optimization of as-cast microstructure, processing and performance remains a challenge for some Al-based alloys. In this context, placement of chills in castings has been frequently used to locally manipulate the solidification conditions and microstructure of a casting.In this work, the effect of using an active copper chill on the residual strain profile of a sand-cast B319 aluminum alloy was investigated. Wedge-shaped castings were produced with three different cooling conditions: copper plate chill, copper pipe with cooling water and no chill (baseline). The effect of chill condition on the variation of residual strain in the casting was investigated using neutron diffraction approach. Diffraction from (111) and (311) reflections was studied and revealed that the (311) reflection did not exhibit appreciable strain variation at different chill conditions. In contrast, theā€¦
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