X-ray CT for microstructure characterization of light metals

Transcription

1 Institute of Materials Science and Technology Vienna University of Technology X-ray CT for microstructure characterization of light metals Robert Koos, Guillermo Requena Institute of Materials Science and Technology Vienna University of Technology - Austria [email protected], [email protected]

2 Properties of multiphase materials 2 AlMg alloy Al/C/65f 60 µm In multiphase materials Properties = f Architecture prop., vol.fract., distr., shape, size, interconnectivity, contiguity,...

3 X-ray -based tomography Lab- XCT High resolution Non-destructive Larger volumes Reveal and Al Time resolution Synchrotron Tomography Why Synchrotron Tomography for metallurgical investigations? - Coherence phase contrast e.g. holotomography - High Brilliance real time (in situ) experiments, ultra fast acquisition times - Tunability posibility of using monochromatic beam, use of the most suitable energy for a certain experiment/material - Combination with other techniques available at the beamline (e.g. diffraction) 3

4 T [ C] Microstructure of cast Al- alloys a Liquid L+a Al- system ~12.6 wt% 577 C a Gehalt in Gew% Weight Percent licon r Al = 2.7 g/cm³ r =2.3 g/cm³ E Al(RT) =70 GPa E Al(300 C) =50GPa E (RT-300 C) =150 GPa L+ Al12 as cast a-al 100 µm 4h 540 C Deep etching of Al Eutectic can be highly interconnected Destructive Qualitative 50µm J. Bell, W. Winegrad, Nature 5006 (1965) 177 s 02Al ~ 50 MPa s 02 ~ MPa CTE Al(RT-300 C) ~ 24 ppm/k CTE (RT-300 C) ~ 3ppm/K Al12 4h/540 C 100 µm Eutectic spheroidises gets rounder and disintegrates 4

5 Microstructure of cast Al- alloys ID19 ESRF / Energy = 29 kev / voxel size = (0.3 µm)³ Resolution ~ 1µm Non-destructive (same sample!) Larger volumes than FIB D Phase contrast tomography e.g.holotomography using three distances as cast 540 C / 4h as cast 540 C / 4h Requena, Garcés, Rodríguez, Pirling, Cloetens, AdvEngMat 11 (12) (2009) 5

6 Strength of cast Al- alloys Compression tests (RT) As cast 540 C/4h equena, Garcés, Rodríguez, Pirling, Cloetens, AdvEngMat 11 (12) (2009) 6

7 Light Optical Tomography ~ (0.1x0.1x0.5) µm³ Al12Ni-AC IM Synchrotron Tomography (0.3x0.3x0.3) µm³ Largest particle after 540 C/24h Al C/24h Al12Ni 540 C/24h IM Al12Ni-540 C/24h IM Synchrotron Tomography (0.3x0.3x0.3) µm³ (vol=290x170x88 (vol=290x170x43µm³) -Total volume fraction of aluminides ~ 8vol% -High degree of interconnectivity and contiguity after 24h/540 C Asghar, Requena, Degischer, Cloetens Acta Materialia 57 (2009) Al10Cu5NiFe - Al 2 Cu - Al 3 CuNi -Al 8 FeMg Al 15 (FeMn) 3 2 Light Optical Tomography+EDX (vol=290x170x43µm³) Vox size ~ (0.4x0.4x1 µm)³ Asghar, Requena, Boller Acta Materialia 59 (2011) Asghar, Requena, Boller Prakt Met 47 (2010) 7

8 Strength of AlNi cast Al- alloys alloys Addition of Cu, Ni, Fe to Al- alloys to form stable aluminides Al12Ni1 Al10Cu5Ni1 Al10Cu5Ni2 licon Aluminide Aluminium Aluminides Al 50 µm 50 µm 50 µm Al Aluminides Composite-like behaviour: -Al matrix (low strength but ductile) - Eutectic - different Aluminides Reinforcement (high strength and E) Strength (540 C/Xhs) 300 C ~15% ~100% ~50% Asghar, Requena, Kubel Mat Sci Eng A 527 (2010) Asghar, Requena, Boller Acta Materialia 59 (2011) 8

9 Strength of cast Al- alloys Volume fraction (%) Al12Ni Al10Cu5Ni1 Al10Cu5Ni2 300 C ~15% Al10Cu5Ni1-2 4h ST Time Aluminides ~100% ~25% Asghar, Requena, Boller Acta Materialia 59 (2011) Aluminides+ Alloys 9

10 3D Elemental sensitive imaging SSRL Beamline 6-2 Absorption edge contrast ESRF ID19 vox = (0.3 µm)³ Aluminides network Sample prepared by FIB Cu-Ni Aluminide 8.25 kev 8.4 kev Ni kev 9.15 kev Cu Vox size ~ (24nm)³ Resol.~ 60nm 5 µm Liu, Mairer, Requena et al. Anal.&Bional.Chemistry,

11 In situ solution treatment of Al- alloys Incoming beam sample Rotation stage 600µm (0.28 µm)³/voxel 0h 1h 4h Al12Cu5Ni2 α-al Aluminides Al17Cu4 α-al Aluminides 50µm 11

12 In situ solution treatment of Al- alloys 12 Stability of aluminides and their morphology after exposure 500 C Hypereutectic alloy Al17Cu4 Dissolution of Al 2 Cu Spheroidisation 0h 1h 4h Al12Cu5Ni2 piston alloy Network of Aluminides stable during ST at 500 C 0h 1h 4h

13 In situ tensile test of Al- alloys Al17Cu4 alloy α-al Aluminides σ Incoming beam tensile test sample Rotation stage ID19 ESRF 100 µm (1.4µm)³/voxel, 10s/tomo 500µm Formation and growth of cracks and pores 13 13

14 In situ solidification of Al- alloys Window Furnace (fixed) AlMg58 alloy Incoming beam sample Rotation stage ID19-ID15 ESRF α-al α-al/mg 2 eutectic α-al/mg 2 / triple eutectic Tolnai, Requena, et al. Acta Mater (2012) cooling rate 5K/min, (1.4µm)³/voxel, 10s/tomo Dendrites Mg µm Triple eutectic 14

15 In situ solidification of Al- alloys Evolution of a-al dendrites with Temp cooling rate 5K/min, (1.4µm³)/voxel, 10s/tomo a-al dendrite coarsening + growing together Tolnai, Townsend, Requena, Lendvai, Degischer Acta Mater (2012) 15

16 In situ solidification of Al- alloys Evolution of Mg 2 with Temp 565 C 555 C Mg 2 nucleate in different positions in between the a-al dendrites 750 µm 750 µm 545 C 540 C finally grow together 750 µm 750 µm Tolnai, Townsend, Requena, Lendvai, Degischer Acta Mater (2012) 16

17 Summary 17 2D characterization is sometimes not enough 3D characterization of heterogeneous materials is necessary for cases where: -The connectivity of the phases and/or contiguity between phases must be analysed. These two parameters can play a decisive role on the mechanical properties of heterogeneous lightweight materials. -The physical sectioning of the material would affect its internal state (e.g. distribution of internal stresses during loading, thermal cycling, etc.) -New in situ characterization methods have opened new opportunities to help to understand dynamic processes.

18 18 Acknowledgements Vienna Group:, Pere Barriobero Vila, David Canelo Yubero, (Hans Peter Degischer), Ricardo Fernández Gutiérrez, Robert Koos, (Georg Fiedler), Marta Rodríguez Hortalá, (Zahid Asghar), Johannes Jonke, (Maya Jaber), Edith Asiemo, Christian Zaruba External: G. Garcés (CENIM-Madrid), D. Tolnai (HZG-Germany), F. Sket (IMDEA-Madrid), L. Salvo (INP-Grenoble), E. Maire, J. Adriane, C. Landron (INSA-Lyon), C. Poletti, Fernando Warchomicka (TU-Graz), Michael Schöbel (TUM-FRMII) Beamline Scientists Elodie Boller (ESRF-ID19) Peter Cloetens (ESRF-ID19, ID22) Marco Di Michiel (ESRF-ID15) Mario Scheel (ESRF-ID15) Thomas Buslaps (ESRF-ID15) Thilo Pirling (ILL-Salsa) Florian Meirer (SSRL-6-2) Andreas Stark (DESY) Norbert Schell (P07-DESY) In tu study of damage in a CFR- Polymer M. Rodríguez Hortalá, G. Requena, F. Sket

19 THANK YOU! 19