TY - JOUR
T1 - Plastic deformation of single crystals of Pt3Al with the L1 2 structure
AU - Okamoto, Norihiko L.
AU - Hasegawa, Yoshihiko
AU - Hashimoto, Wataro
AU - Inui, Haruyuki
N1 - Funding Information:
This work was supported by Grant-in-Aid for Scientific Research (A) (No. 21246101 and No. 21360337) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) Japan and in part by the Global COE (Center of Excellence) Program of International Center for Integrated Research and Advanced Education in Materials Science from the MEXT Japan. The authors are grateful to Dr. K. Tanaka of Kobe University for allowing us to use the apparatus for the measurement of the elastic constants.
PY - 2013/1/1
Y1 - 2013/1/1
N2 - The plastic deformation behaviour of single crystals of Pt3 Al with the L12 structure having an off-stoichiometric composition of Pt-27 at% Al has been investigated in compression from 77 to 1073 K. The L1 2 structure is not stable below around 220 K, transforming into either a D0c or D0c′ structure. Slip occurs along 1 1 0 both on (0 0 1) and on (1 1 1) with slip on (0 0 1) being the primary slip system, which operates for most crystal orientations except for near [0 0 1], accompanied by a considerably lower CRSS (critical resolved shear stress). The CRSS tends to decrease gradually with increasing temperature for both slip in the temperature range where the L12 phase is stable, except for a moderate increase in CRSS observed above 673 K for slip on (0 0 1). Dislocations with b = [1̄ 0 1] dissociate into two collinear superpartials with b = 1/2[1̄ 0 1] separated by an APB on the corresponding slip plane for both slip on (0 0 1) and (1 1 1). For slip on (1 1 1), dislocations tend to align along their screw orientation at room temperature, suggesting the high Peierls stress for their motion. The possibility of showing the normal (large negative) temperature dependence of CRSS at low temperatures as well as the reason for the absence of the anomalous (positive) temperature dependence of CRSS for slip on (1 1 1) at high temperatures is discussed.
AB - The plastic deformation behaviour of single crystals of Pt3 Al with the L12 structure having an off-stoichiometric composition of Pt-27 at% Al has been investigated in compression from 77 to 1073 K. The L1 2 structure is not stable below around 220 K, transforming into either a D0c or D0c′ structure. Slip occurs along 1 1 0 both on (0 0 1) and on (1 1 1) with slip on (0 0 1) being the primary slip system, which operates for most crystal orientations except for near [0 0 1], accompanied by a considerably lower CRSS (critical resolved shear stress). The CRSS tends to decrease gradually with increasing temperature for both slip in the temperature range where the L12 phase is stable, except for a moderate increase in CRSS observed above 673 K for slip on (0 0 1). Dislocations with b = [1̄ 0 1] dissociate into two collinear superpartials with b = 1/2[1̄ 0 1] separated by an APB on the corresponding slip plane for both slip on (0 0 1) and (1 1 1). For slip on (1 1 1), dislocations tend to align along their screw orientation at room temperature, suggesting the high Peierls stress for their motion. The possibility of showing the normal (large negative) temperature dependence of CRSS at low temperatures as well as the reason for the absence of the anomalous (positive) temperature dependence of CRSS for slip on (1 1 1) at high temperatures is discussed.
KW - Compression deformation behaviour
KW - Dislocation
KW - Intermetallic compound
KW - PtAl
KW - Transmission electron microscopy
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U2 - 10.1080/14786435.2012.705037
DO - 10.1080/14786435.2012.705037
M3 - Article
AN - SCOPUS:84872279511
VL - 93
SP - 60
EP - 81
JO - Philosophical Magazine
JF - Philosophical Magazine
SN - 1478-6435
IS - 1-3
ER -