Sponsored by
A Deep Look Into Materials: High Energy X-rays in Metallurgy H. Reichert
X-RAY SCIENCE The electromagnetic spectrum
X-RAY SOURCE DEVELOPMENT : STORAGE RINGS …….. 1 2 1 2 ESRF UP (2015) 1 2 storage ring performance Averge Brillance (photons/s/mm 2 /mrad 2 /0.1%BW ) ESRF (2015) 1 2 (ESRF) Third 1 1 Generation 1 1 ESRF (1994) 1 1 Synchrotron 1 1 Second generation Radiation 1 1 1 1 First generation 1 1 1 1 1 1 1 1 X-ray tubes 1 9 1 8 1 7 1 6 1900 1920 1940 1960 1980 2000
AN INTERNATIONAL GOVERNANCE 21 PARTNER COUNTRIES 13 Member states: France 27.5 % 24 % Germany Italy 13.2 % United Kingdom 10.5 % Russia 6 % Benesync 5.8 % (Belgium, The Netherlands) Nordsync 5 % (Denmark, Finland, Norway, Sweden) Spain 4 % Switzerland 4 % 8 Associate countries: Israel 1.5 % Austria 1.3 % Centralsync 1.05 % (Czech Republic, Hungary, Slovakia) Poland 1 % Portugal 1 % South Africa 0.3 % Legal status: Private non-profit civil company subject to French law
THE ESRF IN A NUTSHELL Partnership between 21 countries World’s most productive synchrotron laboratory Research in all areas involving condensed matter, materials, and living matter ~30 public beamlines (instruments); 14 CRG beamlines (national teams) 600 Staff: 500 with a technical background, 60 post-docs, 40 PhD students ~8000 user visits for ~1500 projects ~1900 publications / year Annual budget: ~100 M€ including the Upgrade Programme
UP PI 2013: new beamline’s portfolio HIGH ENERGY X-RAYS Beamline portfolio beam size cm – mm – µ m – nm up to 700 keV ASD Ima magi ging Diffra ract ctio ion Spectro rosco copy py ID16A+B
STRAIN SCANNING BY ENERGY DISPERSIVE DIFFRACTION • Diffraction peaks arising from all phases measured simultaneously by two Ge solid- state detectors • Energy range: 50-500keV • Spatial resolution 0.05 × 0.05 × 0.50mm 3 − 0.2 × 0.2 × 2.0mm 3 • Acquisition time per point: 30-200s
STRAIN SCANNING BY ENERGY DISPERSIVE DIFFRACTION STRAIN SCANNING • Large samples: penetration up to 10 cm of steel • Spatial resolution down to 0.05 × 0.05 × 0.50mm 3 • Strain resolution: 2 . 10 -4 D UNLOP AIRCRAFT WHEEL (Ø50cm×50cm, 30 KG ) R OLLS R OYCE T RENT -700 CHORD FAN BLADE (T I -6A L -4V) A IRBUS L ANDING GEAR PISTON ROD 900×400×20mm3
STRAIN MAPPING NEAR THE SURFACE Single Laser Shock Peened impact on Ti-6Al-4V • G AUGE VOLUME DEFINED BY SLITS AND THE ANALYSER CRYSTAL Koichi Akita, Tokyo Institute of ⇒ NO “ PSEUDOSTRAIN ” DUE TO PARTIALLY FILLED GAUGE Technology VOLUME NEAR THE SURFACE Radial strain • S UPERIOR RESOLUTION ENHANCES THE STRAIN RESOLUTION AND ENABLES PEAK SHAPE ANALYSIS • D EPTH SENSITIVITY BY CHANGING THE ENERGY AND EXPLOITING THE ABSORPTION EDGES H ARD X- RAYS FOR SURFACE SENSITIVITY H IGH E NERGY X- RAYS FOR DEEP PENETRATION FWHM
The ESRF has a long-standing tradition in in-situ materials testing We study the evolution of the structure of a wide range of Materials • Metals/alloys • Composites • Polymers • Semiconductors • Biomaterials under • mechanical, • thermal, • electrical load or in changing environmental conditions
MATERIALS TENSILE TESTING RIGS ETMT 50 kN Servo hydraulic
MICRO-COMPRESSION DEVICE From static load to dynamic cyclic fatigue
Materials Processing
NB 3 SN SUPERCONDUCTORS void Nb 3 Sn filament Nb-Ti SC with 8.3T maximum field strength to be replaced by Nb 3 Sn (15T) Thermal treatment of Nb 3 Sn strands leads to formation of voids Void growth in operation leads to degradation and failure Development of optimised heat treatment cycles.
EXPERIMENTAL SETUP 2-D diffraction detector monochromatic x-ray beam 88 keV Laue mono sample Laue mono in furnace white x-ray beam tomography detector
Cu 6 Sn 5 (2 0 2) x-ray diffraction x-ray microtomography Sn (2 0 0) Sn (1 0 1) Nb (1 1 0) Cu 5.6 Sn (1 1 1) Cu 541 Sn 11 (6 6 0) Cu (1 1 1) Sn (2 1 1) Cu 5.6 Sn (2 0 0) Cu (2 0 0) Nb (2 0 0) Cu 3 Sn (0 16 0) Cu 5.6 Sn (1 1 2) Cu 6 Sn 5 (2 0 6) Cu 3 Sn (0 8 3) Nb (2 1 1) Cu (2 2 0) 5 h-540 ° C Nb (2 0 0) Cu 5.6 Sn (1 1 3) 420 ° C 540 ° C 230 ° C Cu (3 1 1) 3D view of the voids formed inside the IT Variation of the diffraction patterns of the IT strand at different HT temperatures. Nb 3 Sn strand during Cu–Sn mixing HT cycle.
The void formation mechanisms could be identified by correlating the quantitative void growth results (tomography) with the quantitative description of the phase transformations (diffraction) Void volume is clearly correlated with the Cu 3 Sn content in the strand.
MELT PROCESSING OF BI-2212 POWDER-IN-TUBE SUPERCONDUCTORS XRD-CT PERFORMANCE • Superconductors based on Ag Bi 2 Sr 2 CaCu 2 O x (Bi-2212) can achieve Bi-2212 filaments high critical current densities at very high magnetic fields • Bi-2212 is the only high temperature superconductor that can be produced in the form of round wires, which makes Bi-2212 particularly interesting for high energy physics applications, MRI scanners, power infrastructures in densely populated urban areas, etc • In order to achieve Bi-2212 filament connectivity, the Powder-in-Tube wire Tomographic cross section is submitted to a heat treatment, through an as-drawn Bi-2212 during which the powder melts at PIT wire (before HT) about 880 °C. F. Kametani et al., Supercond. Sci. Technol. 24 , 075009 (2011) C. Scheuerlein et al., Supercond. Sci. Technol . 24 115004 (2011)
EXPERIMENTAL The void and phase evolution is studied by combined diffraction and tomography with a monochromatic 70 keV beam. ramp rate 25 K/h in air Transverse tomographic cross section through a fully processed Sequence of diffractograms acquired Bi-2212 PIT wire during in-situ HT of a Bi-2212 wire in air
RESULTS • Bi-2212 melts in the temperature range 867-882 °C. Bi-2212 re-nucleation during cooling is observed between 863-842 °C. Bi-2201 is detected during cooling below 850 °C. • During the melt processing of Bi-2212 superconductors large voids agglomerate from residual powder porosity. • These voids reduce the filament connectivity and have been identified as major current limiting mechanism in round Bi-2212 wires. 915 °C 20 °C 875 °C Tomographic cross sections acquired before and after in-situ HT to T max = 875 °C (partial Bi-2212 melting) and T max = 915 °C (complete Bi-2212 melting).
HIGH TEMPERATURE SUPERCONDUCTORS FOR HIGH MAGNETIC FIELDS The use of HTS is limited by HTS-based conductors can be fabricated only as thin, their high cost and laborious flat tapes in which grain boundary alignment plays a fabrication process dominant role for the ability to carry large currents. New method found for processing round wires of Bi-2212 to increase current density by means of a very high overpressure process during the heat treatment of the material Overall conductor current X-ray tomograms 1 bar pores Bi-2212 Ag 100 bar Extensive porosity found in the wire The eightfold increase in J E is due to processed under 1 bar the elimination of leakage and No porosity and high density found suppression of the void porosity in a wire processed at 100 bar D. C. Larbalestier et al., Nature Materials, 13 (2014) 375-381
UP PI 2013: new beamline’s portfolio TIME RESOLUTION Beamline portfolio Time resolution spans 15 orders of magnitude! 10 -10 - 10 5 sec from milli-seconds to nano-seconds Imaging Crystallography Scattering Spectroscopy ID16A+B
FUSION WELDING – MILLISECOND RANGE Sample: Fe–Cr–17.3% Ni–11.1% Mo–2.1% C < 0.1% austenitic steel Beam energy : 50-150keV 1 x 0.1 mm 2 Beam size : Detector: CMOS sensor coupled to Imaging Intensifier Frame rate: 1kHz
IN-SITU MEASUREMENT
RESULTS weld cross-section micrographs sectioned along the beam direction. (a) Full weld cross-section from a post-experimental sample. (b) Half-cross section detailing an experimental weld pool. The grains form predominantly at the melt–solid interface and grow into the X-ray illuminated region Time evolution of angular velocities for six re-orienting crystals. Bragg spot angular rotations are up to 10 4 times larger than expected from thermal contraction, stresses or any other change of the lattice parameter → mainly due to rigid body rotation Ultrafast moving Blocked columnar crystals Moving columnar free crystals (only thermal contraction) crystals
RESULTS Evolution of growth and tilting for four representative columnar type crystals . Conclusion : substantial crystal rotation, tilting and motion occurs, especially in the earlier stages of solidification strong influence on the transient behavior of growing crystals in welds W. U. Mirihanage et al., Acta Mater. 68 (2014) 159-168
Recommend
More recommend
