Spark Plasma Sintering of High-Energy Ball-Milled ZrB₂ and HfB₂ Powders with 20vol% SiC

Abstract:

ZrB₂ and HfB₂ with incorporation of SiC are being considered as structural materials for elevated temperature applications. We used high energy ball milling of micron-size powders to increase lattice distortion enhanced inter-diffusion to get uniform distribution of SiC and reduce grain growth during Spark Plasma Sintering (SPS). High-energy planetary ball milling was performed on ZrB₂ or HfB₂ with 20vol% SiC powders for 24 and 48 hrs. The particle size distribution and crystal micro-strain were examined using Dynamic Light Scattering Technique and x-ray diffraction (XRD), respectively. XRD spectra were analyzed using Williamson-Hall plots to estimate the crystal micro-strain. The particle size decreased, and the crystal micro-strain increased with the increasing ball milling time. The SPS consolidation was performed at 32 MPa and 2,000°C. The SEM observation showed a tremendous decrease in SiC segregation and a reduction in grain size due to high energy ball milling of the precursor powders. Flexural strength of the SPS consolidated composites were studied using Four-Point Bend Beam test, and the micro-hardness was measured using Vickers micro-indenter with 1,000 gf load. Good correlation is observed in SPS consolidated ZrB₂+SiC with increased micro-strain as the ball milling time increased: grain size decreased (from 9.7 to 3.2 μm), flexural strength (from 54 to 426 MPa) and micro-hardness (from 1528 to 1952 VHN) increased. The correlation is less evident in HfB₂+SiC composites, especially in micro-hardness which showed a decrease with increasing ball milling time.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 1990-1995
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.1990
• Online since: December 2018
• Authors: Naidu Seetala*, Cyerra L. Prevo, Lawrence E. Matson, Thomas S. Key, Ilseok I. Park
• Keywords: Flexural Strength, Grain Size, High-Energy Ball-Milling, Micro-Hardness, Micro-Strain, Spark Plasma Sintering

References

[1] W. G. Fahrenholtz, G. E. Hilmas, I. G. Talmy, and J. A. Zaykoski, Refractory diborides of zirconium and hafnium, J. Am. Ceram. Soc. 90 (2007) 1347-1364.

DOI: 10.1111/j.1551-2916.2007.01583.x

[2] Q. Liu, W. Han, X. Zhang, S. Wang, and J. Han, Microstructure and mechanical properties of ZrB2-SiC composites, Materials Letters 63 (2009) 1323-1325.

DOI: 10.1016/j.matlet.2009.02.054

[3] R. Licheri, R. Orrù, A. M. Locci, and G. Cao, Efficient synthesis/sintering routes to obtain fully dense ZrB2-SiC ultra-high-temperature ceramics, Ind. Eng. Chem. Res. 46 (2007) 9087-9096.

DOI: 10.1021/ie0701423

[4] R. Licheri, R. Orrù, C. Musa, A. M. Locci, and G. Cao, Consolidation via spark plasma sintering of HfB2/SiC and HfB2/HfC/SiC composite powders obtained by self-propagating high-temperature synthesis, J. Alloys Compd. 478 (2009) 572-578.

DOI: 10.1016/j.jallcom.2008.11.092

[5] N. V. Seetala and M. T. Webb, Spark plasma heat treated ZrB2-SiC and HfB2-SiC composites, Materials Science Forum 783-786 (2014) 1176.

DOI: 10.4028/www.scientific.net/msf.783-786.1176

[6] N. Seetala, M. Webb, L. Matson, H. Lee, C. Carney, and T. Key, Spark plasma heat treated coarse and nano-powder ZrB2-SiC and HfB2-SiC composites, Bulk Processing of Nanostructured Powders and Nano-powders by Consolidation Symposium, 2016 TMS Proceedings.

DOI: 10.1017/s1431927615006054

[7] N. Seetala, O. Reedy, L. Matson, H. Lee, T. Key, Effect of argon gas purging of spark plasma sintered ZrB2+SiC nano-powder composites", in Characterization of Minerals, Metals, and Materials 2017, S. Ikhmayies et al (Eds.), The Minerals, Metals & Materials Series, pp.171-178.

DOI: 10.1007/978-3-319-51382-9_19

[8] N. V. Seetala, O. Reedy, L. E. Matson, and H. Lee, High-energy ball-milling of ZrB2 and HfB2 powders: effect on particle size and crystal strain distribution, Microscopy and Microanalysis 22-S3 (2016) 1870-1871.

DOI: 10.1017/s1431927616010199

[9] A. K. Zak, W.H. A. Majid, M.E. Abrishami, R. Yousefi, X-ray analysis of ZnO nanoparticles by Williamson–Hall and size–strain plot methods, Solid State Sciences 13 (2011) 251-256.

DOI: 10.1016/j.solidstatesciences.2010.11.024

[10] F. T. Muniz, M. A. Miranda, C. M. D. Santos, J. M. Sasaki, The Scherrer equation and the dynamical theory of X-ray diffraction, Acta Crystallogr A Found Adv. 72 (2016) 385-390.

DOI: 10.1107/s205327331600365x

[11] Y. Zhou, J. Wang, Z. Li, X. Zhan, and J. Wang, First-Principles Investigation on the Chemical Bonding and Intrinsic Elastic Properties of Transition Metal Diborides TMB2 (TM=Zr, Hf, Nb, Ta, and Y), p-60, in W. G. Fahrenholtz, E. J. Wuchina, W. E. Lee, and Y. Zhou (Eds.), Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications, Wiley (2014).

DOI: 10.1002/9781118700853.ch4