Dr-Schmitz by chenmeixiu


  (Control of microstructure in solders)


presented at the COST 531 WG6 meeting
       Berlin , January 14th 2003

        ACCESS Materials&Processes
                 Intzestr 5
         D-52072 Aachen, Germany
•   private,non-profit research association,
•   originated from Foundry Institute of RWTH Aachen in 1986
•   annual turnover 2001 approx 5 million €
•   actually approx. 60 employees (35 scientists, > 7 disciplines)
•   interests in materials& processes :

            „anything related to solidfication“


active:             former
                    (or less active)
M. Apel
                    U. Grafe
B. Böttger
H.-J. Diepers
                    B. Nestler
J. Eiken (Tiaden)
                    F. Pezzolla
P. Schaffnit
I. Steinbach
                    M. Seeßelberg
N. Warnken
         The "Aachen" Phase Field Model

               =                     +

real system         thermodynamics        interfaces


Directional Growth of a 3-D Dendrite in Al-Si7

                          T = 20 K/mm
                         v = 5 mm/s
                         anisotropy 30% in kinetics

                                         200 m

                                                r = 3 m

Results of H.J.Diepers
.Model Description:   Schematic View on Thermodynamic Coupling
 Coupling with Thermodynamic Databases (II)


 dT/dt =

 200 m

                                              x(Nb) %

 Results of B.Böttger
 Coupling with Thermodynamic Databases (III)


  Results of B.Böttger
   Ternary Eutectics

  System Al-Ag-Cu

   Eutectic compositon:

Liquid: Al, at% =   69,9647
        Ag, at% =   16,9674
        Cu, at% =   13,0679
        Te      =   775,71 K

  Results of M.Apel
  fcc + hcp + Q     Cu   Ag

Results of M.Apel
       Ternary eutectics:
EXPERIMENTAL example: Ag-Cu-Zn
• former and present areas of activity related to solders

    –   melt atomization of BiSn powders
    –   solder contacts to superconductors
    –   solder contacts to solar cells
    –   soldering of single crystalline superalloys
    –   laser surface welding
    –   directional solidification studies Bi-In-Sn system

• future activities
    – „CONTROLDER“ : Experiments, Analytics, Microsimulation
    – „NOPLEES“     :Thermodynamics
                    „Controlder“ OBJECTIVES
•macroscopic issues of solder joints
    • sessile drop experiments/wetting                     To propose
    • mesoscopic self-assembly
                                                       and to develop
    • solidification in confined geometries
                                                      effective means
• microstructure formation in solder alloys
                                                            to control
    • directional solidification
    • thermal cycling                         microstructure formation
    • doping effects                                   in solder joints
    • interaction with solder pads
    • generation/avoidance of precipitates
    • others.....
• numerical simulations
    •microstructure evolution
    •thermoelectric aging
  No Plumbum Equilibrium and Environment Search
NIST Solder Database: Ag - Bi - Cu - Sn - Pb
Binary     Ag-Bi, Ag-Pb, Bi-Cu, Bi-Sn, Cu-Sn, Ag-Cu, Ag-Sn, Bi-Pb, Cu-Pb, Sn-Pb
Ternary    Ag-Bi-Cu, Ag-Bi-Sn, Ag-Cu-Sn, Bi-Cu-Pb, Bi-Pb-Sn, Ag-Bi-Pb, Ag-Cu-Pb,
           Ag-Pb-Sn, Bi-Cu-Sn, Cu-Pb-Sn
Updated Systems (Zimmermann 1976) Relevant for Solders: Ag - Bi - Cu - Pb - Tl
Binary     Ag-Bi, Ag-Cu, Ag-Pb, Ag-Tl, Bi-Cu, Bi-Pb, Bi-Tl
Ternary    Ag-Bi-Pb, Ag-Bi-Tl, Ag-Pb-Tl, Bi-Pb-Tl
Additional Set to Investigate New Solder Alloys, Ag - Al - Mg - Sn - Zn
Binary     Ag-Al, Ag-Mg, Ag-Sn, Ag-Zn, Al-Mg, Al-Sn, Al-Zn, Mg-Sn, Mg-Zn, Sn-Zn
Ternary    Ag-Al-Mg, Ag-Al-Sn, Ag-Al-Zn, Ag-Mg-Sn, Ag-Mg-Zn, Ag-Sn-Zn, Al-Mg-Sn,
           Al-Mg-Zn, Al-Sn-Zn, Mg-Sn-Zn
Systems with Cu Relevant for Soldes and Substrate, Ag - Al - Cu - Zn
Binary     Ag-Al, Ag-Cu, Ag-Zn, Al-Cu, Al-Zn, Cu-Zn
Ternary    Ag-Al-Cu, Ag-Al-Zn, Ag-Cu-Zn, Al-Cu-Zn
                     NOPLEES Coordination:
                     Suzana G. Fries
                                                Finacial and
   Partners:                                    Scientific
                                                Support Agencies

Dr. Matsvei Zinkevich


Dr. Marie-Christine Record


             „Noplees“ and „Controlder“ Status

•bilateral German (Aachen,Stuttgart) -French (Montpellier) project submitted end
Jan 2002 (CERC3, DFG-CNRS)
•focus on thermodynamics
•tentative duration : 3 years
•final decision on funding still pending

•focus on experimental work and microstructure control
•no national project submitted by now
•open for collaboration
                Possible Collaborative Groupings
Melt composition/Thermodynamics: WG 1+2,                    TU Chemnitz (D12), Univ
Sofia (BG1), Univ. Metz (F4), Univ Krakow(PL2), Chalmers (S1) , ACCESS (D2)

Processing :
•general Siemens (D9),
•solid state processing :
      •solderpaste printing Univ Dresden (D11)
      • diffusion soldering Polish Academy (PL1),
      • transient LiquidPhase Sintering Univ Waterloo (CDN4)
•melt properties:
      •elctrical conductivity Univ. Metz (F4),
      •viscosity, surface tension, density Univ. Metz (F4), TU Chemnitz (D14), Univ
      Krakow (PL2, PL4)
      • dopants TU Chemnitz (D12), Univ Sofia (BG1), ACCESS (D3) , Chalmers (S1)
     •seed additions Univ. Metz (F4),
     •thermal history TU Chemnitz (D14) Univ. Metz (F4),
•process atmosphere: Univ Sofia (BG1) Univ Dresden (D11) , ACCESS (D3)
                   Possible Collaborative Groupings
      •T-t schedules: TU Chemnitz (D12), whisker formation Shipley (CH3), ACCESS (D3) , Univ.
      Metz (F4), ICMCB (F6) Slovak Academy (SK1) Open Univ (UK5) Univ Waterloo (CDN5),
      Univ Dresden (D11)
      •solidifcation boundary conditions:
      PWB: Slovak Academy (SK1)Univ Toronto (CDN3), Univ Waterloo (CDN5), Univ Dresden
      (D11) Siemens (D8),
      component Univ Dresden (D11)Siemens (D8),
      geometry ACCESS (D3),
      size Polish Academy (PL1) Univ Augsburg (D7), Univ Vienna(A3), ACCESS (D3),
      composition Univ Toronto (CDN2) Shipley (CH3), ACCESS (D3),
      wetting TU Chemnitz (D12), TU Chemnitz (D14), Univ. Metz (F4), Univ Krakow(PL2)
      Slovak Academy (SK1),
 •solid state transformations:
      •recrystallization/grain growth Univ Toronto (CDN2) Open Univ (UK5)

Microstructure analysis: TU Chemnitz (D12), Univ Toronto (CDN2), ACCESS (D3) , TU
Dresden (D10) Univ Krakow(PL2) Slovak Academy (SK1) Open Univ (UK2) Univ Bordeaux (F5),
                 Possible Collaborative Groupings
Characterization / Reliability:
•general Siemens (D8),
•aging :
     •long term heat treatments TU Chemnitz (D12) TU Dresden (D10) Univ Dresden (D11) Univ
     Waterloo (CDN5) Univ Bordeaux (F5),
     • thermal cycling/fatigue Univ. Toronto (CDN1) Chalmers (S1), Siemens (D9) Univ
     Vienna(A3), Fraunhofer IZM (D4) Fraunhofer IZM (D5) Univ Berlin (D6) Open Univ (UK1)
     • cyclic mechanical load: Univ Augsburg (D7) , Siemens (D9) Fraunhofer IZM (D5)
     • creep TU Dresden (D10), ICMCB (F6), Open Univ (UK2) Fraunhofer IZM (D5) Univ Berlin
• mechanical properties EMPA (CH2) Siemens (D9), Univ Krakow(PL2) Chalmers (S1) Slovak
Academy (SK1) Open Univ (UK2) Univ Vienna(A3),
• electrical properties Siemens (D9), Univ Krakow(PL2) Chalmers (S1)
• thermal properties Slovak Academy (SK1)
• stresses/cracking Univ Augsburg (D7) Open Univ (UK1)
• corrosion EMPA (CH2) Chalmers (S1)
                 Possible Collaborative Groupings

•analytic expressions Open Univ (UK2)
•melt properties: TU Chemnitz (D14)

•microstructure formation: ACCESS (D3), Bulgarian Academy (BG2), Fraunhofer IZM (D4)
•creep Siemens (D9),
•fatigue Chalmers (S1) , Bulgarian Academy (BG2)
•stresses - strains Univ Berlin (D6)
•thermomechanical Fraunhofer IZM (D5) Univ Berlin (D6) Univ Bordeaux (F5),
•mechanistic history Open Univ (UK2)
•thermoelectric history ACCESS (D3) :
Current distributions in multiphase systems:
    effects on electric load on life-time
        Confined spaces/self-assembly

                  75% of 220 crystals well-
1 mm
                  oriented over the area 8-9 mm2

                                                       Twin plane

                                                   a                b

                                             E.A.Goodilin, E.S.Reddy,
                                             J.G.Noudem,M.Tarka ,G.J.Schmitz
       H.O.Jacobs, A.R.Tao, A.Schwartz,
                                             Journal of Crystal Growth 241(2002)512
       Science 296(2002)323 (April 2002)

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