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Author Cao, S.; Somsen, C.; Croitoru, M.; Schryvers, D.; Eggeler, G. pdf  doi
openurl 
  Title Focused ion beam/scanning electron microscopy tomography and conventional transmission electron microscopy assessment of Ni4Ti3 morphology in compression-aged Ni-rich Ni-Ti single crystals Type A1 Journal article
  Year (down) 2010 Publication Scripta materialia Abbreviated Journal Scripta Mater  
  Volume 62 Issue 6 Pages 399-402  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract The size, morphology and configuration of Ni4Ti3 precipitates in a single-crystal NiTi alloy have been investigated by two-dimensional transmission electron microscopy-based image analysis and three-dimensional reconstruction from slice-and-view images obtained in a focused ion beam/scanning electron microscopy (FIB/SEM) dual-beam system. Average distances between the precipitates measured along the compression direction correlate well between both techniques, while particle shape and configuration data is best obtained from FIB/SEM. Precipitates form pockets of B2 of 0.54 ìm in the compression direction and 1 ìm perpendicular to the compression direction.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Oxford Editor  
  Language Wos 000275072700020 Publication Date 2009-12-04  
  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 16 Open Access  
  Notes Fwo Approved Most recent IF: 3.747; 2010 IF: 2.820  
  Call Number UA @ lucian @ c:irua:79817 Serial 1246  
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Author Cao, S.; Nishida, M.; Somsen, C.; Eggeler, G.; Schryvers, D. doi  openurl
  Title 3D FIB/SEM study of Ni4Ti3 precipitates in Ni-Ti alloys with different thermal-mechanical histories Type P1 Proceeding
  Year (down) 2009 Publication Abbreviated Journal  
  Volume Issue Pages 02004,1-02004,6  
  Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)  
  Abstract The three-dimensional size, morphology and distribution of Ni4Ti3 precipitates growing in binary Ni-rich Ni-Ti alloys have been investigated via a slice view procedure in a Dual-Beam FIB/SEM system, in order to better stress-free Ni50.8Ti49.2 alloy with all four variants of precipitates and a compressed Ni51Ti49 alloy with aligned precipitates in one family were studied. The Ni4Ti3 precipitates reach a volume fraction of 9.6% in the reconstructed region of the stress-free alloy and 4.3% in the compressed one. In both cases, the mean volume, specific surface area, sphericity and aspect ratio of the precipitates are calculated and the Pair Distribution Functions of the precipitates are obtained. It is shown that most precipitates in the stress-free sample grow larger and have a more lenticular shape, while those in the compressed sample are more cylindrical. Deviations from these ideal shapes reveal internal steps in the stress-free sample and lamellae formation in the compressed one.  
  Address  
  Corporate Author Thesis  
  Publisher Edp Place of Publication Coutaboeuf Editor  
  Language Wos 000274582300008 Publication Date 2009-08-31  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 1 Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:81950 c:irua:81950 Serial 14  
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Author Somsen, C.; Wassermann, E.F.; Kästner, J.; Schryvers, D. doi  openurl
  Title Precursor phenomena in a quenched and aged Ni52Ti48 shape memory alloy Type A1 Journal article
  Year (down) 2003 Publication Journal de physique: 4 T2 – 10th International Conference on Martensitic Transformations, JUN 10-14, 2002, ESPOO, FINLAND Abbreviated Journal J Phys Iv  
  Volume 112 Issue Part 2 Pages 777-780  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We measured the electrical resistivity R(T) and specific heat C-p(T) between room temperature (RT) and 4.2 K as well as the microstructure by transmission electron microscopy (TEM) of a Ni-52 Ti-48 SMA quenched from 1000degreesC (B2-Phase range) to RT and then annealed for 1h at T=380degreesC, 550degreesC and 650degreesC. In the “as quenched” and the “650degreesC annealed” state no martensitic transformations (MT's) occur. The diffraction patterns show faint reflections originating from coherent Ni4Ti3 precipitates in an early state of formation. Additional reflections of the type 1/2 <110>, 1/2 <111> and 1/3 <110> result from various lattice displacement waves, which are precursors of the MT's to the B19' and R-phase, respectively. Indeed, high resolution TEM micrographs of the [001] zone of the “as quenched” sample reveal transverse 1/2 <110> <110> lattice displacement waves, precursors of the B19' martensite. The coherent Ni4Ti3 precipitates, homogeneously distributed on a small length scale, binder the MT's in the “as quenched” and the “650degreesC annealed” state, and thus only the precursors appear. When annealed at T=380degreesC, however, coherent Ni4Ti3 precipitates with a length of 10nm are clearly visible in TEM. These precipitates trigger the NIT from the B2 to the R-phase on cooling, as evidenced also by anomalies in R(T) and C-p(T). Annealing at T-550degreesC leads to the well known two step MT's from the B2 to the R-phase and then into the B19'-phase. These martensitic transitions are clearly seen as additional peaks in the specific heat and anomalies in the resistance, while the “as quenched” and 650degreesC annealed samples show weak features in R(T) and C-p(T).  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Les Ulis Editor  
  Language Wos 000186503400036 Publication Date 2008-08-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1155-4339; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 2 Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:102791 Serial 2694  
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Author Somsen, C.; Kästner, J.; Wassermann, E.F.; Boullay, P.; Schryvers, D. pdf  doi
openurl 
  Title Microstructure of quenched Ni-rich Ni-Ti shape memory alloys Type A1 Journal article
  Year (down) 2001 Publication Journal de physique: 4 T2 – 8th European Symposium on Martensitic Transformations (ESOMAT2000), SEP 04-08, 2000, COMO, ITALY Abbreviated Journal J Phys Iv  
  Volume 11 Issue Pr8 Pages 445-449  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Microstructural investigations with transmission electron microscopy were carried out on quenched Ni-Ti alloys with 52 and 54.5 at% Ni. For the Ni52Ti48 specimen long time exposed diffraction patterns of a single grain show besides the expected reflections of the B2-phase, two sets of extra reflections in different zones. The first type of spots is explained by lattice displacement waves, which are regarded as precursors of the martensitic Ni-Ti phases, B 19' and R-phase, respectively. The second set of reflection with more diffuse intensity than the other reflections is related to Ni4Ti3 precipitates in an early state of formation. For the Ni-richer Ni54.5Ti45.5 alloy only Ni4Ti3 precipitates in an early state of formation are found but no precursors of the B 19'- and R-phase.  
  Address  
  Corporate Author Thesis  
  Publisher E d p sciences Place of Publication Les ulis cedexa Editor  
  Language Wos 000173253800075 Publication Date 2007-09-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1155-4339; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 2 Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:104187 Serial 2073  
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