TY - JOUR
T1 - Fracture and property relationships in the double diboride ceramic composites by spark plasma sintering of TiB 2 and NbB 2
AU - Demirskyi, Dmytro
AU - Solodkyi, Ievgen
AU - Nishimura, Toshiyuki
AU - Vasylkiv, Oleg O.
PY - 2019/7
Y1 - 2019/7
N2 - Bulk titanium diboride–niobium diboride ceramic composites were consolidated by spark plasma sintering (SPS) at 1950°C. SPS resulted in dense specimens with a density exceeding 98% of the theoretical density and a multimodal grain size ranging from 1 to 10 µm. During the SPS consolidation, the pressure was applied and released at 1950 and 1250°C, respectively. This allowed obtaining a two-phase composite consisting of TiB 2 and NbB 2 . For these ceramics composites, we evaluated the flexural strength and fracture toughness and room and elevated temperatures. Room-temperature strength of thus produced bulks was between 300 and 330 MPa, at 1200°C or 1600°C an increase in strength up to 400 MPa was observed. Microstructure after flexure at elevated temperatures revealed the appearance of the needle-shape subgrains of NbB 2 , an evidence for ongoing plastic deformation. TiB 2 –NbB 2 composites had elastic loading stress curves at 1600°C, and at 1800°C fractured in the plastic manner, and strength was ranged from 300 to 450 MPa. These data were compared with a specimen where a (Ti,Nb)B 2 solid solution was formed during SPS to explain the behavior of TiB 2 –NbB 2 ceramic composites at elevated temperatures.
AB - Bulk titanium diboride–niobium diboride ceramic composites were consolidated by spark plasma sintering (SPS) at 1950°C. SPS resulted in dense specimens with a density exceeding 98% of the theoretical density and a multimodal grain size ranging from 1 to 10 µm. During the SPS consolidation, the pressure was applied and released at 1950 and 1250°C, respectively. This allowed obtaining a two-phase composite consisting of TiB 2 and NbB 2 . For these ceramics composites, we evaluated the flexural strength and fracture toughness and room and elevated temperatures. Room-temperature strength of thus produced bulks was between 300 and 330 MPa, at 1200°C or 1600°C an increase in strength up to 400 MPa was observed. Microstructure after flexure at elevated temperatures revealed the appearance of the needle-shape subgrains of NbB 2 , an evidence for ongoing plastic deformation. TiB 2 –NbB 2 composites had elastic loading stress curves at 1600°C, and at 1800°C fractured in the plastic manner, and strength was ranged from 300 to 450 MPa. These data were compared with a specimen where a (Ti,Nb)B 2 solid solution was formed during SPS to explain the behavior of TiB 2 –NbB 2 ceramic composites at elevated temperatures.
KW - composite
KW - elevated temperature strength
KW - flexural strength
KW - niobium diboride
KW - titanium diboride
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U2 - 10.1111/jace.16276
DO - 10.1111/jace.16276
M3 - Article
AN - SCOPUS:85060034362
VL - 102
SP - 4259
EP - 4271
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
SN - 0002-7820
IS - 7
ER -