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Mapping polycrystalline materials in 3D: Diffraction contrast tomography and related techniques Andrew King ! Synchrotron SOLEIL W. Ludwig, P. Reischig, L. Nervo, S. Schmiederer, N. Viganò, Y. Guilhem, G. Johnson and many others… Outline • Introduction • Motivation • Underlying techniques • Diffraction contrast tomography – Setup, data acquisition and processing • Application examples • Developments in progress • Related techniques 1 Myself • Diffraction for strain, stress and damage characterisation – Manchester 2001-2005 • Tomography for 3D morphology of porous and granular materials – INSA de Lyon 2006 • Diffraction Contrast Tomography for mapping polycrystals and materials applications. – Manchester/ESRF/HZG 2009-2013 • At SOLEIL since 2013… – PSICHE beamline, tomography for materials science Outline • Introduction • Motivation • Underlying techniques • Diffraction contrast tomography – Setup, data acquisition and processing • Application examples • Developments in progress • Related techniques 2 450 S. Terzi et al. / Scripta Materialia 61 (2009) 449–452 serted into alumina tubes and fixed with ceramic glue. In The liquid regions have been outlined in blue. At the on- order to localize the deformation of the specimen in the set of deformation, time t0, the liquid of near-eutectic region of interest where X-ray images are recorded, the composition is fairly homogeneously distributed within cross-section of the specimen was locally reduced to the whole specimen. The measured volume fraction of about 1.5 mm in diameter (i.e. a notched zone). The liquid, typically 7–8%, can be compared to the theoreti- specimen was heated by an induction coil and the tem- cal value predicted by two microsegregation models. At perature was controlled and monitored by using a ther- the temperature of 555 °C, the liquid fraction is equal to mocouple 0.5 mm in diameter inserted into the lower 9% under equilibrium conditions, whereas the Scheil– alumina tube and in close contact with the specimen. Gulliver model gives 17%. The measured value is closer 1 The specimen was heated at 0.5 °CsÀ up to 555 °C, to the equilibrium value, which seems to indicate that i.e. aboveWhat the are eutectic we trying temperature to do, (548 and°C), why? and then the heating plus holding times were sufficient to homog- held isothermally for 3 min at this temperature to reach enize the initial copper concentration profiles of the thermal• homogenization. Imaging materials The tensile test was then per- solidified specimen. However, perfect homogenization 1 formed at a displacement speed of 0.1 lmsÀ which should not be achieved if one calculates the correspond- – How are they structured? 4 1 leads to an average strain rate equal to 2 10À sÀ , ing Fourier number Fo (Fo < 0.1). Furthermore, the assuming that– How the gauge does length the structure of the specimen determine is equal propertiesmeasured and liquid fraction is even lower than the equilib- to 0.5 mm. behaviour? rium value. This can be explained by the fact that some During the– How tensile does test, the the structure tensile rig andchange the speci-during use?of the liquid remains in the form of intergranular films men were allowed to rotate through 180° in 16 s, while which are too thin to be detected by X-ray tomography. the heating450 coil itself was fixed. DuringS. Terzi et al. / Scriptathis Materialia rotation, 61 (2009) 449–452 The next three images of Figure 1 show the same 400 transmission450 serted into alumina images tubes of and the fixedS. Terzi zone with etal. ceramic / Scripta of interestglue. Materialia In 61 (2009) ofThe theliquid 449–452 regionsnotched have been outlined region in blue. at At various the on- times (or levels) of deforma- specimen wereorder to localize recorded. the deformation The of pixel the specimen size in wasthe setset of to deformation,tion. time t0 As, the deformation liquid of near-eutectic proceeds, the fraction of liquid serted intoregion alumina of interest tubes where and fixed X-ray with images ceramic are glue. recorded, In theThe liquidcomposition regions have is fairly been homogeneously outlined in blue. distributed At the on- within 2.8 lm.order Such tocross-section localize scans the ofdeformation the the specimen specimen of the was specimen locally were in reduced the recorded toset ofthe deformation, every whole specimen. timeint0, The the measured liquid deformed of near-eutectic volume fraction zone of increases. In other words, since 450 S. Terzi et al. / Scripta Materialia 61 (2009) 449–452 27 s usingregionabout of the interest 1.5 latest mm where in version X-ray diameter images (i.e. of are a notchedthe recorded, Camera zone). the Thecomposition FReLoNliquid, is typically fairly homogeneously 7–8%,the can solid be compared distributed skeleton to within the experiencestheoreti- plastic deformation with 450 serted into alumina tubes and fixedS.cross-section Terzi with etspecimen al. ceramic / Scripta of glue. Materialiawas the In heated specimen 61 (2009) byThe an was liquid 449–452 induction locally regions reduced coil have and been to the outlined tem-the whole incal blue. value specimen. At thepredicted on- The by measured two microsegregation volume fraction models. of At F2kHD-Atmelaboutperature 1.5 mm with inwas diameter controlled a fast (i.e. and readout amonitored notched zone). of by using the The a CCD ther-liquid, camerathe typically temperature 7–8%, ofcan 555 bev° comparedC,> the 0, liquid liquid to thefraction theoreti- flows is equal to into the notched region (i.e. serted intoorder alumina to localize tubes the and deformation fixed with ceramic of the specimen glue. In in theThe liquidset of regions deformation, have been time outlinedt0, the in liquidblue. At of the near-eutectic on- $ s region of interest where X-ray imagesspecimen aremocouple recorded,was heated 0.5 the mm by an1 in inductioncomposition diameter coilinserted is and fairly theinto homogeneously tem- the lowercal value distributed9% predicted under within equilibrium by twoÁ microsegregation conditions, whereas models. the At Scheil– order to localize the deformationset of at the specimen 20 Mpixels in the set sÀ of deformation,[15]. After time t0, data the liquid acquisition, of near-eutectic $ v < 0) in order to ensure global mass conservation. cross-section of the specimen wasperature locallyalumina was reduced controlled tube toand and inthe closemonitored whole contact specimen. by withusing the a The ther- specimen. measuredthe temperature volumeGulliver fraction model of 555 of gives°C, the 17%.‘ liquid The fraction measured is equal value to is closer region of interest where X-ray images are recorded, the composition is fairly homogeneously1 distributed within Á about 1.5 mm in diameterthree-dimensional (i.e.mocouple a notchedThe 0.5 specimen zone). mm Thein (3-D) was diameter heatedliquid, images inserted at typically 0.5 ° intoCs of 7–8%,À the theup lower can to specimen 555 be compared°C,9% underto to were the the equilibrium equilibrium theoreti- conditions,At value, the which whereas longest seems the to Scheil– indicatetime (i.e.that about 900 s or 18% average cross-section of the specimen was locallyalumina reducedi.e. tube above toand the in eutecticthe close whole contact temperature specimen. with the (548The specimen.° measuredC), and then volumeGulliver fractionthe model heating of gives plus 17%. holding The timesmeasured were value sufficient is closer to homog- specimen was heated by an induction coil and the tem- cal value predicted1 by two microsegregation models. At about 1.5 mm in diameter (i.e. a notchedThe specimen zone). The was heatedliquid, at typically 0.5 Cs 7–8%,À up can to 555 be comparedC, to to the the equilibrium theoreti- value, which seems to indicate that perature was controlledreconstructed and monitoredheld by using isothermally using a ther- standard for 3the min temperature° at this reconstruction temperature of 555 °°C, to the reach liquid tools. fractionenize In isthe equal initial to copperdeformation concentration of profiles the specimen) of the a few pores or cracks have specimen was heated by an induction coili.e.• and abovethermalThis the the tem- eutectichomogenization.coverscal temperature value a predictedlot The (548 tensileof by°materialsC), test two and was microsegregation then then per-science!the heating models.solidified plus At holding specimen. times However, were suffi perfectcient to homogenization homog- mocouple 0.5 mm in diameteraddition inserted to into direct the lower post-processing9% under equilibrium ofthese conditions,1 images whereas the to Scheil– already appeared in the notched area. This is shown in perature was controlled and monitoredheld by using isothermallyformed a ther- atfor a displacement 3the min temperature at this speedtemperature of 555 of 0.1°C, tol thems reach liquidÀ which fractionenize istheshould equal initial not to copper be achieved concentration if one calculates profiles the of correspond- the alumina tube and in close contact with the specimen. Gulliver model gives 17%. The4 measured1 value is closer mocouple 0.5 mm in diameterquantify insertedthermal into theleads the1 homogenization. lower evolution to an average9% Theunder strainof tensile equilibrium the rate test equal microstructure, was conditions, to then 2 per-10À whereassÀ solidified, specific theing Scheil– specimen. Fourier number However,moreFo perfect( detailFo < 0.1). homogenization in Furthermore,Figure 2 the, where a sequence of 2-D images The specimen was heated at 0.5 °CsÀ up to 555 °C, to the equilibrium1 value, which seems to indicate that alumina tube and in close contact withformed theassuming specimen. at a displacement that theGulliver gauge speed model length of gives 0.1of thelms 17%. specimenÀ Thewhich measured is equalshould valuemeasured not is closer be achieved liquidfraction if one calculates is even lower the correspond- than the equilib- i.e. above the eutectic temperature1 (548 °C), and then the heating plus holding4 times1 were sufficient to homog- The specimen was heated atvolumetric 0.5 °CsÀleadsup toto digital555 an0.5 averagemm.°C, image strainto the rate equilibrium correlation equal to value, 2 10 which(V-DIC)À sÀ , seemsing to has indicate Fourierrium been value.

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