Densification mechanisms during reactive spark plasma sintering of Titanium diboride and Zirconium diboride. Issue 19 (3rd July 2017)

• Record Type: Journal Article
• Authors: Karthiselva, N. S.; Kashyap, Sanjay; Yadav, Devinder; Murty, B. S.; Bakshi, Srinivasa R.
• Is Part Of: Philosophical magazine. Volume 97:Issue 19(2017)
• Page Start: 1588
• Page End: 1609
• Publication Date: 2017-07-03
• Subjects: Borides -- reactive spark plasma sintering -- densification -- ceramics -- EBSD; Condensed matter -- Periodicals; Physics -- Periodicals; Matière condensée -- Périodiques; Physique -- Périodiques; 530.41
• DOI: 10.1080/14786435.2017.1312022
• Languages: English
• ISSNs: 1478-6435

Abstract

Abstract: In this study, dense fine-grained ZrB2 and TiB2 were fabricated using reactive spark plasma sintering (RSPS) of ball-milled Zr/B and Ti/B mixtures. Systematic investigations were carried out to understand the mechanisms of reactive sintering. Two densification mechanisms were found to be operating during RSPS. The first stage of densification was due to self-propagating high temperature synthesis reaction leading to formation of ZrB2 and TiB2 compacts having relative density of ~48 and ~65%, respectively. The second stage of densification occurred at temperatures more than 1100 °C and resulted in final relative density of more than 98%. Electron backscatter diffraction and electron microscopy studies on interrupted RSPS samples as well as dense samples showed deformed grains and presence of slip steps while grain orientation spread map and pole figure analysis confirmed plastic flow. Plastic flow-aided pore closure is shown as major mechanism during reactive sintering.