heat treating of niti shape memory alloys - eventos.fct.unl.pt · ni-ti system ligas ricas em ti...
TRANSCRIPT
Francisco M. Braz Fernandes
Heat Treating of NiTi Shape Memory Alloys
Ni-Ti System
Ligasricas em Ti
Ligasricas em Ni
W. Tang, B. Sundman, R. Sandström, C. Qiu. Acta materialia 47 (1999) 3457-3468
Austenite(B2)
Cubic
Martensite(B19’)
Monoclinic
R-phase(R)
Rhombohedral
-20 0 20 40 60 80 100 120 140-500-400-300-200-100
0100200300400500600700
Hea
t Flo
w (W
/g) x
10-3
Temperature (ºC)-60 -40 -20 0 20 40 60 80
-300-250-200-150-100-50
050
100150200250300
Hea
t Flo
w (W
/g) x
10-3
Temperature (ºC)-60 -40 -20 0 20 40 60
-300-250-200-150-100-50
050
100150200250300
Hea
t Flo
w (W
/g) x
10-3
Temperature (ºC)-80 -60 -40 -20 0 20 40 60
-300-250-200-150-100-50
050
100150200250300
Hea
t Flo
w (W
/g) x
10-3
Temperature (ºC)
AR 400C 450C 500C 550C 600C-30-15
0153045607590
105120135150
Tran
sfor
mat
ion
Tem
pera
ture
(ºC
)
Sample ConditionAR 400C 450C 500C 550C 600C
-60-45-30-15
0153045607590
Tran
sfor
mat
ion
Tem
pera
ture
(ºC
)
Sample ConditionAR 400C 450C 500C 550C 600C
-75-60-45-30-15
015304560
Tran
sfor
mat
ion
Tem
pera
ture
(ºC
)
Sample ConditionAR 400C 450C 500C 550C 600C
-90-75-60-45-30-15
015304560
Tran
sfor
mat
ion
Tem
pera
ture
(ºC
)Sample Condition
IncreasingIncreasing NiNi contentcontent
Heat treatments / chemical composition
[347] FanG, ChenW, Yang S, Zhu J, RenX, Otsuka K. Acta Mater 2004;52:4351.
Precipitation
HeatHeat TreatmentTreatmentTemperatureTemperature: : 350350ººC C 450450ººCC 550550ººCC
Functionally Graded Materials
Thermomechanical treatments
× / +× / +⊗ / ⊕⊗ / ⊕⊗ / ⊕600ºC
×× / +×× / +× / +× / ⊕⊗ / ⊕550ºC
×× / +×× / +× / +× / ⊕⊗ / ⊕500ºC
×× / +×× / +×× / +×× / +× / ⊕450ºC×× / +×× / +×× / +×× / +×× / ⊕400ºC×× / +×× / +×× / +×× / +×× / ⊕AR
Alloy “N”(51.0 at% Ni)
Alloy “S”(50.8 at% Ni)
Alloy “B”(50.2 – 50.4 at% Ni)
Alloy “M”(49.8 – 50.0 at% Ni)
Alloy “H”(49.4 – 49.6 at% Ni)
Phase Transformation on Cooling / on HeatingSample
Condition
× / +× / +⊗ / ⊕⊗ / ⊕⊗ / ⊕600ºC
×× / +×× / +× / +× / ⊕⊗ / ⊕550ºC
×× / +×× / +× / +× / ⊕⊗ / ⊕500ºC
×× / +×× / +×× / +×× / +× / ⊕450ºC×× / +×× / +×× / +×× / +×× / ⊕400ºC×× / +×× / +×× / +×× / +×× / ⊕AR
Alloy “N”(51.0 at% Ni)
Alloy “S”(50.8 at% Ni)
Alloy “B”(50.2 – 50.4 at% Ni)
Alloy “M”(49.8 – 50.0 at% Ni)
Alloy “H”(49.4 – 49.6 at% Ni)
Phase Transformation on Cooling / on HeatingSample
Condition
-40 -20 0 20 40 60 80 100 120-300-250-200-150-100-50
050
100150200250300
Hea
t Flo
w (W
/g) x
10-3
Temperature (ºC)AR 400C 450C 500C 550C 600C
-30-15
0153045607590
105120
Tran
sfor
mat
ion
Tem
pera
ture
(ºC
)
Sample Condition
εε(N=1) (N=1) = = 0,610,61
Severe Plastic DeformationECAP (Equal Channel Angular Pressing)
HeCeTo
Severe Plastic DeformationECAP (Equal Channel Angular Pressing)
XRD
2- Theta º
Resultados
2- Theta º
Resultados
2- Theta º
Resultados
2- Theta º
PowderMetallurgy
AcknowledgementsA. Pereira (CENIMAT)A.S. Paula (CENIMAT, now with Universidade Federal Fluminense – UFF),C. Baetz (ROBL – ESRF; HZDR),F. Neves (CENIMAT, now with LNEG),K.K. Mahesh (CENIMAT, now with Vivekananda College of Engineering & Technology), M.T. Nogueira (CENIMAT),N. Schell (P07-PETRA, HZG), R.J.C. Silva (CENIMAT),R.M.S. Martins (CENIMAT, ITN),