Micro-Chemistry Simulation of Al-Alloys with the ClaNG-Model. Olaf Engler, Hydro RDB GTT Workshop, Herzogenrath,

Transcription

1 Micro-Chemistry Simulation of Al-Alloys with the ClaNG-Model Olaf Engler, Hydro RDB GTT Workshop, Herzogenrath,

2 Micro-Chemistry Simulation of Al-Alloys with the ClaNG-Model Outline Introduction: micro-chemistry simulation of Al-alloys The ClaNG-model Application example: homogenisation of Al alloy 86 to improve the recrystallization behaviour (2) OE

3 Hydro: a leading integrated aluminium and energy company Gaining primary aluminium Casting and recycling Fabricating aluminium Bauxite & Alumina Energy Primary Metal Metal Markets Rolled Products Extruded Products Soon better equity in alumina Solid long-term coverage of power 1% hydropower in Norway 1.4 mill. mt/year 1 metal plants in 5 countries on 3 continents 4 35 employees Up to 2.4 mill. mt/year Primary + cold metal +.5 mill. mt recycling metal Special alloys 11 remelters in 5 countries 1. mill. + 3, mt/year Operations in more than 3 countries 13 3 employees Solar energy Rolled Products with own remelting Equity Long-term power supply Cost position Technology Expertise in materials Technology Recycling Close to customers Service, Quality and Innovation Production figures are from 29 (3) OE

4 Hydro: a key player in rolled products We operate leading rolling assets, foremost in Europe New York Holmestrand Karmoy Stockholm 6 plants in 4 countries + Alunorf, the world s largest aluminium rolling mill (5%) 2 R&D Centres Malaysia Slagelse Wolverhampton Huizen Hamburg Sao Paulo Norf/GV Bonn Krakow Paris Neuhausen Barcelona Cisterna Rolling Mill Sales Office R&D We employ around 4, We ship up to 1 million tonnes per year 77% to customers in Europe 17% market share in Europe 1 1 Estimate based on EAA data (4) OE

5 We serve a wide range of applications Litho Plain strip and sheet for offset printing plates Packaging and building Plain and lacquered strip for cans and other packaging containers Plain and converted foil for flexible packaging and technical applications Plain and lacquered strip, sheet and plate for architecture: Facades, roller shutters, etc. Automotive, heat exchanger and general engineering Plain, anodised and cladded strip and sheet for cars, transport and heat exchanger systems general engineering, solar technology and special industry (5) OE

6 Industrial production of Al sheet process chain DC casting homogenisation hot rolling cold rolling annealing DC casting sheet ingot breakdown rolling mill sexto cold mill batch furnace finished coil (6) OE tandem hot rolling line

7 Through-Process Modelling DC casting homogenisation hot rolling cold rolling annealing Main metallurgical reactions along the process chain homogenisation: diffusion, microchemistry (solutes, phases) hot rolling: work hardening, softening, texture, microchemistry cold rolling: work hardening, texture back-annealing: softening, texture microchemistry work hardening softening (7) OE

8 BMBF Project ClaNG Plus Duration: Start: End: Partners Hydro Aluminium Rolled Products GmbH, R&D Bonn (project management) Institut für Metallkunde und Metallphysik, RWTH Aachen GTT-Technologies, Herzogenrath Workpackages: 1. Model development ClaNG (IMM, Hydro) 2. Link of ClaNG model to modern multi component thermodynamic data bases (IMM, GTT, Hydro) 3. Link of ClaNG model to property models (IMM, Hydro) 4. Evaluation of applicability to solidification (IMM, Hydro) 5. Full scale trials and characterization (Hydro, IMM) (8) OE

9 ClaNG Modell Classical Nucleation and Growth model overview Goal: determine the precipitation kinetics classical theories: Nucleation: Becker and Döring Growth: Zener Evolution of precipitate size distributions: continuity equation (Kampmann and Wagner) Decision based on thermodynamic calculations using ChemApp (GTT Technologies) Data base: Thermotech AlTT (8 elements: Al-Cr-Cu-Fe-Mg-Mn-Si-Ti) developed by L. Löchte (RDB), G. Gottstein (IMM) and M. Schneider (Diss. IMM, 26), advanced by E. Jannot (Diss. IMM, 28) and Z.S. Liu (Diss. 211) (9) OE

10 ClaNG Modell Classical Nucleation and Growth model overview INPUT Starting state: Alloy concentrations Primary phase volume fraction (density & size) Dendrite arm spacing Physical parameter: Phase diagram Diffusivity Interfacial energies Industrial process: Time-Temperature curve (dislocation density) Thermodynamic * Free Energy curves Equilibrium calculation Nucleation State at time t Temperature, Alloy conc Growth & Coarsening State at time t + t New conc., phase vol. frac Kinetic Diffusion Phase Composition Update OUTPUT Matrix: Alloy concentrations Primary & secondary phases: Volume fraction (density and size distribution) Composition Material properties: Conductivity * : performed using ChemApp (GTT) (1) OE

11 Al alloy AA 86 (AlFe1.5Mn) Medium strength foil alloy (semiridgid packaging applications, menue trays, candle lights, ) Fin stock header / inlet tube header / outlet corrugated lamellae (11) OE

12 Recrystallization of AA 86 Experiments 7 homogenisation C2 H1 L1 6 Experiments 5 Alloy: AA 86 (AlFe1.5Mn.5) as-cast material (DC-cast) homogenisation trials L1 (6 C) 3 H1 (48 C) C2 (6 C/5 C) water quenching cold rolling to 2.mm (9%) back-annealing 2 4 C T [ C] back-annealing t [s] cold rolling (12) OE

13 Recrystallization of AA 86 Metallography as-cast / homogenised Grain diameter 183 µm Cell diameter 25 µm as-cast homogenised H1 (48 C) (13) OE C2 (6 C/5 C) L1 (6 C)

14 Recrystallization of AA 86 Metallography 7 6 C2 H1 L1 el. conductivity / resistivity 5 4 T [ C] t [s] (14) OE

15 Recrystallization of AA 86 Thermodynamic simulation equilibrium Scheil Al 6 Mn Al 3 Fe α-al(fe,mn)si Al 3 Fe Al 6 Mn α-al(fe,mn)si (15) OE

16 Recrystallization of AA 86 microprobe analysis Summary Al 3 (Fe,Mn):.9% Fe/Mn >1:1 Al 6 (Mn,Fe): 4.5% Fe/Mn 4~5:1 α-al(fe,mn)si (16) OE

17 AA 86 microprobe / element-maps (H1, 48 C) (17) OE

18 AA 86 microprobe / element-maps (L1, 6 C) (18) OE

19 Recrystallization of AA 86 electrical resistivity ρ 4. 2 K α Mn c Mn α 4.2K Mn = µω cm / wt% H1 C2 L1 Reihe4.3.3 µωcm] ρ4.2k [µ n [%] cmn.2.1. Guss homogenisiert wh 2 C 25 C 3 C 35 C 4 C (19) OE

20 Recrystallization of AA 86 Thermo-Electric Power (TEP) (2) OE

21 Recrystallization of AA 86 mechanical properties 25 2 H1 C2 L1 [MPa] Rp wh 2 C 225 C 25 C 275 C 3 C 325 C 35 C 375 C 4 C MT [ C] (21) OE

22 Recrystallization of AA 86 Metallography cold rolled, back annealed at 4 C (anodised, longitudinal section, 5:1) H1 (48 C) (22) OE C2 (6 C/5 C) L1 (6 C)

23 Einleitung: ClaNG Modell Classical Nucleation and Growth Prozess-Parameter Zeit Temperatur Versetzungsdichten Thermodynamische Daten Legierung Zustandsdiagramm Diffusionskoeffizienten Grenzflächenenergie dr dt 4 2 G( r C ) = π r C σ 3 2 σ rc = gt α α c(t) c (r) c(t) c (r) D.5 β α c c (r) c c(t) r = β N = N ( ) G rc Z β exp k B T Mikrochemie Lösungszustände c i Ausscheidungen V i (r) Art, Größe, Volumen (23) OE

24 Recrystallization of AA 86 ClaNG simulation constituents (H1) t [h] E-5 t [h] #3 Al 3 Fe #6 Al 6 Mn #9 α-al(fe,mn)si large (>.25µm) Vol [%] T [ C] r [m] 1E T [ C] t [s] 1E t [s] (24) OE

25 Recrystallization of AA 86 ClaNG simulation solids & dispersoids (H1) c ss [%] t [h] Fe Si Mn Fe Si Mn T [ C] Vol [%] size [µm].1 t [h] #9 α-al(mn,fe)si small (<.25µm) 1 Vol 5.1 Temp size T [ C] t [s] 1E-3 72 t [s] (25) OE

26 Recrystallization of AA 86 ClaNG simulation constituents (L1) t [h] t [h] E #3 Al 3 Fe #6 Al 6 Mn #9 α-al(fe,mn)si large (>.25µm) Vol [% %] T [ C] r [m] 1E T [ C] t [s] 1E t [s] (26) OE

27 Recrystallization of AA 86 ClaNG simulation solids & dispersoids (L1) c ss [%] t [h] Fe Si Mn Fe Si Mn T [ C] size [µm] Vol [%] t [h] #9 α-al(fe,mn)si 7 small (<.25µm) 6 size Vol Temp T [ C] t [s] 1E t [s] (27) OE

28 Recrystallization of AA 86 ClaNG simulation constituents (C2) Vol [%] t [h] T [ C] r [m] 3.x x1-6 1.x1-6 t [h] T [ C] #3 Al 3 Fe #6 Al 6 Mn #9 α-al(fe,mn)si large (>.25µm) t [s] t [s] (28) OE

29 Recrystallization of AA 86 ClaNG simulation solids & dispersoids (C2) t [h] Fe Si Mn Fe Si Mn Vol [%] t [h] Vol 1 5 Temp 4.1 c ss [%].15 3 T [ C] 3 T [ C] size [µm].1 size t [s] 1E t [s] (29) OE

30 Recrystallization of AA 86 Summary and Conclusions Homogenisation H1 (48 C): massive precipitation of Mn-bearing secondary phases C2 (6/5 C): (i) precipitation and re-dissolution of Mn-bearing secondary phases, (ii) precipitation of coarse Mn-bearing dispersoids and/or growth of constituents L1 (6 C): precipitation and re-dissolution of Mn-bearing secondary phases Rolling + recrystallisation H1: high density of fine secondary phases strong inhibition of ReX C2: coarse dispersoids minimum inhibition of ReX L1: strong supersaturation but concurrent precipitation medium inhibition of ReX the ClaNG model allows analysing the evolution of microchemistry (solutes, particles) along the process chain of Al-alloys (3) OE

31 (31) OE