TY - JOUR
T1 - Plastic deformation of single crystals of CrB2, TiB2 and ZrB2 with the hexagonal AlB2 structure
AU - Paul, Bhaskar
AU - Okamoto, Norihiko L.
AU - Kusakari, Misato
AU - Chen, Zhenghao
AU - Kishida, Kyosuke
AU - Inui, Haruyuki
AU - Otani, Shigeki
N1 - Funding Information:
This work was supported by Grant-in-Aids for Scientific Research on Innovative Areas on High Entropy Alloys through the grant number JP18H05450 and JP18H05451 , and in part by JSPS KAKENHI grant numbers JP18H01735 , JP18H05478 , JP19H00824 and by the Elements Strategy Initiative for Structural Materials (ESISM) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, grant number JPMXP0112101000 .
Publisher Copyright:
© 2021 Acta Materialia Inc.
PY - 2021/6/1
Y1 - 2021/6/1
N2 - The plastic deformation behavior of single crystals of three transition-metal diborides with the AlB2 structure, CrB2, TiB2 and ZrB2 has been investigated as a function of crystal orientation in the temperature range from room temperature to 1500 °C. Plastic flow is observed above 800 °C by the operation of slip on {11¯00}<112¯3> in CrB2, while in ZrB2, the onset temperature for slip on {11¯00}<112¯3> is 700 °C and that for slip on (0001)<112¯0> is 800 °C. In contrast, any appreciable plastic flow is not observed in TiB2 at 1500 °C and below. The critical resolved shear stress (CRSS) for slip on {11¯00}<112¯3> in CrB2 monotonously decreases with increasing temperature up to 1500 °C. On the other hand, the CRSS for slip on {11¯00}<112¯3> in ZrB2 decreases with increasing temperature up to 1000 °C and then increases anomalously with increasing temperature. Similarly, the CRSS for slip on (0001)<112¯0> in ZrB2 decreases with increasing temperature up to 1200 °C and then increases anomalously with increasing temperature, followed again by the decrease above 1400 °C. Generalized stacking fault (GSF) energy calculations well explain slip direction on the relevant slip plane, dislocation dissociation scheme and relative ease of slip among the three transition-metal diborides. The existence of planar growth faults on prism planes in CrB2 and TiB2 significantly affects the plastic deformation behavior so that the high onset temperature for plastic flow for these two diborides cannot be predicted solely by GSF energy calculations.
AB - The plastic deformation behavior of single crystals of three transition-metal diborides with the AlB2 structure, CrB2, TiB2 and ZrB2 has been investigated as a function of crystal orientation in the temperature range from room temperature to 1500 °C. Plastic flow is observed above 800 °C by the operation of slip on {11¯00}<112¯3> in CrB2, while in ZrB2, the onset temperature for slip on {11¯00}<112¯3> is 700 °C and that for slip on (0001)<112¯0> is 800 °C. In contrast, any appreciable plastic flow is not observed in TiB2 at 1500 °C and below. The critical resolved shear stress (CRSS) for slip on {11¯00}<112¯3> in CrB2 monotonously decreases with increasing temperature up to 1500 °C. On the other hand, the CRSS for slip on {11¯00}<112¯3> in ZrB2 decreases with increasing temperature up to 1000 °C and then increases anomalously with increasing temperature. Similarly, the CRSS for slip on (0001)<112¯0> in ZrB2 decreases with increasing temperature up to 1200 °C and then increases anomalously with increasing temperature, followed again by the decrease above 1400 °C. Generalized stacking fault (GSF) energy calculations well explain slip direction on the relevant slip plane, dislocation dissociation scheme and relative ease of slip among the three transition-metal diborides. The existence of planar growth faults on prism planes in CrB2 and TiB2 significantly affects the plastic deformation behavior so that the high onset temperature for plastic flow for these two diborides cannot be predicted solely by GSF energy calculations.
KW - Dislocations
KW - High-resolution electron microscope (HREM)
KW - High-temperature deformation
KW - Layered structure
KW - Single-crystal
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U2 - 10.1016/j.actamat.2021.116857
DO - 10.1016/j.actamat.2021.116857
M3 - Article
AN - SCOPUS:85103983707
VL - 211
JO - Acta Materialia
JF - Acta Materialia
SN - 1359-6454
M1 - 116857
ER -