Biomedical Engineering Reference
In-Depth Information
M
*
973 K−3.6 ks W.Q.
M
*
(at.%)
Ti−48.7Ni
Cooling
Ti−42.6Ni−5.0Cu
MA
*
O
*
Ti−37.0Ni−9.5Cu
M
*
MA
*
MA
*
O
*
OA
*
Ti−26.6Ni−18.0Cu
Heating
OA
*
200
250
300
350
Temperature (K)
FIGURE 9.33
DSC curves showing transformation behavior in TiNiCu alloy thin films. (From Miyazaki, S., Ishida, A.,
Mater.
Sci. Eng.
, 273-275, 106-133, 1999, with permission from Elsevier.)
The transformation hysteresis, (
MA*-M*
) or (
OA*-O*
), shows a strong dependence on Cu
content, as shown in Figure 9.34. A stronger Cu dependence of the hysteresis is observed
in the single-stage transformation region than in the two-stage transformation region. The
hysteresis decreases from 27 to 11 K with increasing Cu content from 0 to 9.5 at.%, and this
property is comparable to that of bulk specimens.
Figure 9.35 shows the strain versus temperature (
ε
-T
) curves for Ti-Ni-Cu alloy thin
films measured during cooling and heating under a variety of constant stresses. The
ε
-T
curves measured under the same stresses (60, 120, 180 MPa) in each specimen are shown
TABLE 9.3
Lattice Parameters of Ti-37.0Ni-9.5Cu (at.%)
a
(nm)
b
(nm)
c
(nm)
α
(°)
β
(°)
γ
(°)
B2
0.3032
0.3032
0.3032
90.00
90.00
90.00
Orthorhombic
0.2875
0.4198
0.4508
90.00
90.00
90.00
Monoclinic
0.3031
0.4254
0.4828
90.00
96.96
90.00
Source:
Miyazaki, S., Ishida, A.,
Mater. Sci. Eng. A
, 273-275, 106-133, 1999, with permission from Elsevier.
