TY - JOUR
T1 - Slip Resistance of Ti-Based High-Temperature Shape Memory Alloys
AU - Ojha, A.
AU - Sehitoglu, H.
N1 - Funding Information:
The support from Nyquist Chair Fund and partial support from National Science Foundation grant NSF CMMI-1333884 are gratefully acknowledged. We thank Mr. George Li for providing assistance with the LDT simulations setup.
Funding Information:
The support from Nyquist Chair Fund and partial support from National Science Foundation grant NSF CMMI-1333884 are gratefully acknowledged. We thank Mr. George Li for providing assistance with the LDT simulations setup.
Publisher Copyright:
© 2016, ASM International.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - Titanium with Nb, Zr, and Ta alloying substitutions possesses high plastic slip resistance and high transformation strains upon bcc (β) to orthorhombic (α″) transformation. In the current study, we determine the critical resolved shear stress (CRSS) for slip in Ti alloyed for a wide composition range of Nb, Ta, and Zr. The CRSS is obtained with a proposed Peierls–Nabarro formalism incorporating the generalized stacking fault energy barrier profile for slip obtained from the first-principles Density Functional Theory (DFT) calculations. The CRSS for slip of the orthorhombic martensite increases from 80 to 280 MPa linearly with increasing unstable fault energy. The addition of tantalum is most effective in raising the energy barriers. We also demonstrate the composition dependence of the lattice parameters of both β and α″ crystal structures as a function of Nb, Ta, and Zr additions showing agreement with experiments. Using the lattice constants, the transformation strain is determined as high as 11 % in the [011] pole and its magnitude increases mainly with Zr addition.
AB - Titanium with Nb, Zr, and Ta alloying substitutions possesses high plastic slip resistance and high transformation strains upon bcc (β) to orthorhombic (α″) transformation. In the current study, we determine the critical resolved shear stress (CRSS) for slip in Ti alloyed for a wide composition range of Nb, Ta, and Zr. The CRSS is obtained with a proposed Peierls–Nabarro formalism incorporating the generalized stacking fault energy barrier profile for slip obtained from the first-principles Density Functional Theory (DFT) calculations. The CRSS for slip of the orthorhombic martensite increases from 80 to 280 MPa linearly with increasing unstable fault energy. The addition of tantalum is most effective in raising the energy barriers. We also demonstrate the composition dependence of the lattice parameters of both β and α″ crystal structures as a function of Nb, Ta, and Zr additions showing agreement with experiments. Using the lattice constants, the transformation strain is determined as high as 11 % in the [011] pole and its magnitude increases mainly with Zr addition.
KW - Martensite
KW - Shape memory
KW - Slip
KW - Superelasticity
KW - Ti–Nb–Ta
KW - Ti–Nb–Zr
KW - Transformation strain
UR - http://www.scopus.com/inward/record.url?scp=84991691197&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84991691197&partnerID=8YFLogxK
U2 - 10.1007/s40830-015-0050-z
DO - 10.1007/s40830-015-0050-z
M3 - Article
AN - SCOPUS:84991691197
SN - 2199-384X
VL - 2
SP - 50
EP - 61
JO - Shape Memory and Superelasticity
JF - Shape Memory and Superelasticity
IS - 1
ER -