Records |
Author |
Lu, J.B.; Shi, H.; Sedlakova-Ignacova, S.; Espinoza, R.; Kopeček, J.; Sittner, P.; Bártová, B.; Schryvers, D. |
Title |
Microstructure and precipitates in annealed Co38Ni33Al29 ferromagnetic shape memory alloy |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Journal of alloys and compounds |
Abbreviated Journal |
J Alloy Compd |
Volume |
572 |
Issue |
|
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
5-10 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Transmission electron microscopy was performed to investigate the microstructure and precipitates in the annealed Co38Ni33Al29 ferromagnetic shape memory alloy. Apart from the dendritic secondary phase in the austenite matrix, micron-sized (up to 100 μm) fcc-based precipitates with partial γ′ L12 ordering and containing none, one or three {1 1 1}p parallel twin planes were found. The orientation relationship between the precipitates and matrix was found to be KurdjumovSachs. STEMEDX analysis indicates that twinned and non-twinned precipitates are Co-rich and Al- and Ni-deficient with respect to the matrix and with a lower Co/Al ratio for the latter. The 3D morphologies of precipitates were reconstructed with focused ion beam/scanning electron microscope dual-beam slice-and-view imaging, showing that the single {1 1 1}p plane twinned precipitates have a plate-like shape while the non-twinned precipitates are lath-like and often bent. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000319209600002 |
Publication Date |
2013-04-02 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0925-8388; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.133 |
Times cited |
10 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.133; 2013 IF: 2.726 |
Call Number |
UA @ lucian @ c:irua:107914 |
Serial |
2058 |
Permanent link to this record |
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|
|
Author |
Bartova, B.; Schryvers, D.; Yang, Z.; Ignacova, S.; Sittner, P. |
Title |
Microstructure and precipitates in as-cast Co38Ni33Al29 shape memory alloy |
Type |
A1 Journal article |
Year |
2007 |
Publication |
Scripta materialia |
Abbreviated Journal |
Scripta Mater |
Volume |
57 |
Issue |
1 |
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
37-40 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Oxford |
Editor |
|
Language |
|
Wos |
000246632900010 |
Publication Date |
2007-04-13 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1359-6462; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.747 |
Times cited |
22 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.747; 2007 IF: 2.481 |
Call Number |
UA @ lucian @ c:irua:64753 |
Serial |
2059 |
Permanent link to this record |
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|
|
Author |
Malard, B.; Pilch, J.; Sittner, P.; Gartnerova, V.; Delville, R.; Schryvers, D.; Curfs, C. |
Title |
Microstructure and functional property changes in thin Ni-Ti wires heat teated by electric current: high energy X-ray and TEM investigations |
Type |
A1 Journal article |
Year |
2009 |
Publication |
Functional materials letters |
Abbreviated Journal |
Funct Mater Lett |
Volume |
2 |
Issue |
2 |
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
45-54 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
High energy synchrotron X-ray diffraction, transmission electron microscopy and mechanical testing were employed to investigate the evolution of microstructure, texture and functional superelastic properties of 0.1 mm thin as drawn NiTi wires subjected to a nonconventional heat treatment by controlled electric current (FTMT-EC method). As drawn NiTi wires were prestrained in tension and exposed to a sequence of short DC power pulses in the millisecond range. The annealing time in the FTMT-EC processing can be very short but the temperature and force could be very high compared to the conventional heat treatment of SMAs. It is shown that the heavily strained, partially amorphous microstructure of the as drawn NiTi wire transforms under the effect of the DC pulse and tensile stress into a wide range of annealed nanosized microstructures depending on the pulse time. The functional superelastic properties and microstructures of the FTMT-EC treated NiTi wire are comparable to those observed in straight annealed wires. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000271077000001 |
Publication Date |
2009-07-22 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1793-6047;1793-7213; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.234 |
Times cited |
21 |
Open Access |
|
Notes |
Multimat |
Approved |
Most recent IF: 1.234; 2009 IF: 2.561 |
Call Number |
UA @ lucian @ c:irua:77656 |
Serial |
2052 |
Permanent link to this record |
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|
|
Author |
Delville, R.; Malard, B.; Pilch, J.; Sittner, P.; Schryvers, D. |
Title |
Transmission electron microscopy investigation of dislocation slip during superelastic cycling of NiTi wires |
Type |
A1 Journal article |
Year |
2011 |
Publication |
International journal of plasticity |
Abbreviated Journal |
Int J Plasticity |
Volume |
27 |
Issue |
2 |
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
282-297 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Superelastic deformation of thin NiTi wires containing various nanograined microstructures was investigated by tensile cyclic loading with in situ evaluation of electric resistivity. Defects created by the superelastic cycling in these wires were analyzed by transmission electron microscopy. The role of dislocation slip in superelastic deformation is discussed. NiTi wires having finest microstructures (grain diameter <100 nm) are highly resistant against dislocation slip, while those with fully recrystallized microstructure and grain size exceeding 200 nm are prone to dislocation slip. The density of the observed dislocation defects increases significantly with increasing grain size. The upper plateau stress of the superelastic stressstrain curves is largely grain size independent from 10 up to 1000 nm. It is hence claimed that the HallPetch relationship fails for the stress-induced martensitic transformation in this grain size range. It is proposed that dislocation slip taking place during superelastic cycling is responsible for the accumulated irreversible strains, cyclic instability and degradation of functional properties. No residual martensite phase was found in the microstructures of superelastically cycled wires by TEM and results of the in situ electric resistance measurements during straining also indirectly suggest that none or very little martensite phase remains in the studied cycled superelastic wires after unloading. The accumulation of dislocation defects, however, does not prevent the superelasticity. It only affects the shape of the stressstrain response, makes it unstable upon cycling and changes the deformation mode from localized to homogeneous. The activity of dislocation slip during superelastic deformation of NiTi increases with increasing test temperature and ultimately destroys the superelasticity as the plateau stress approaches the yield stress for slip. Deformation twins in the austenite phase ({1 1 4} compound twins) were frequently found in cycled wires having largest grain size. It is proposed that they formed in the highly deformed B19′ martensite phase during forward loading and are retained in austenite after unloading. Such twinning would represent an additional deformation mechanism of NiTi yielding residual irrecoverable strains. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Oxford |
Editor |
|
Language |
|
Wos |
000284921800007 |
Publication Date |
2010-05-17 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0749-6419; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.702 |
Times cited |
157 |
Open Access |
|
Notes |
Fwo; Iap |
Approved |
Most recent IF: 5.702; 2011 IF: 4.603 |
Call Number |
UA @ lucian @ c:irua:84651 |
Serial |
3709 |
Permanent link to this record |
|
|
|
Author |
Delville, R.; Malard, B.; Pilch, J.; Sittner, P.; Schryvers, D. |
Title |
Transmission electron microscopy study of microstructural evolution in nanograined Ni-Ti microwires heat treated by electric pulse |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Diffusion and defect data : solid state data : part B : solid state phenomena |
Abbreviated Journal |
|
Volume |
172/174 |
Issue |
|
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
682-687 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Transmission electron microscopy and mechanical testing were employed to investigate the evolution of microstructure and functional superelastic properties of 0.1mm diameter as-drawn Ni-Ti wires subjected to a non-conventional heat treatment by controlled electric pulse current. This method enables a finer control of the recovery and recrystallisation processes taking place during the heat treatment and accordingly a better control on the final microstructure. The best functional properties were obtained for heat-treated Ni-Ti wires having a nanograined microstructure (20-50 nm) partially recovered through polygonization and partially recrystallized. Such microstructure is highly resistant against dislocation slip upon cycling, while microstructures annealed for longer time and showing mostly recrystallized grains were prone to dislocation slip, particularly as the grain size exceeds 100 nm. The density of dislocation defects increased significantly with increasing grain size of the microstructure. The activity of three <100>/{011} slip systems was identified in the largest grains of 500-1200 nm. An additional mode of plastic deformation, {114} compound austenite twinning, was observed in the largest grains of fully recrystallized microstructures. It is proposed that dislocation slip (and possibly deformation twinning) occurring in superelastic cycling is coupled with the stress-induced martensitic transformation. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Vaduz |
Editor |
|
Language |
|
Wos |
000303359700105 |
Publication Date |
2011-07-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1662-9779; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
3 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:90154 |
Serial |
3717 |
Permanent link to this record |
|
|
|
Author |
Malard, B.; Pilch, J.; Sittner, P.; Delville, R.; Curfs, C. |
Title |
In situ investigation of the fast microstructure evolution during electropulse treatment of cold drawn NiTi wires |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
Volume |
59 |
Issue |
4 |
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
1542-1556 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Microstructural changes taking place during the heat treatment of cold-worked NiTi alloy are of key interest in shape memory alloy technology, since they are responsible for setting the austenite shape and functional properties of the heat-treated alloy. In this work, microstructural evolution during non-conventional electropulse heat treatment of thin NiTi filaments was investigated in a unique high-speed in situ synchrotron X-ray diffraction experiment with simultaneous evaluation of the tensile force and electrical resistivity of the treated wire. The in situ results provide direct experimental evidence on the evolution of the internal stress and density of defects during fast heating from 20 °C to ∼700 °C. This evidence is used to characterize a sequence of dynamic recovery and recrystallization processes responsible for the microstructure and superelastic functional property changes during the electropulse treatments. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Oxford |
Editor |
|
Language |
|
Wos |
000287265100023 |
Publication Date |
2010-12-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1359-6454; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.301 |
Times cited |
48 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 5.301; 2011 IF: 3.755 |
Call Number |
UA @ lucian @ c:irua:98372 |
Serial |
1583 |
Permanent link to this record |
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|
|
Author |
Rotaru, G.-M.; Tirry, W.; Sittner, P.; van Humbeeck, J.; Schryvers, D. |
Title |
Microstructural study of equiatomic PtTi martensite and the discovery of a new long-period structure |
Type |
A1 Journal article |
Year |
2007 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
Volume |
55 |
Issue |
13 |
Pages ![sorted by First Page field, ascending order (up)](img/sort_asc.gif) |
4447-4454 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Oxford |
Editor |
|
Language |
|
Wos |
000248436400021 |
Publication Date |
2007-06-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1359-6454; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.301 |
Times cited |
7 |
Open Access |
|
Notes |
Fwo G.0465.05; Multimat |
Approved |
Most recent IF: 5.301; 2007 IF: 3.624 |
Call Number |
UA @ lucian @ c:irua:65849 |
Serial |
2047 |
Permanent link to this record |