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									Explosive welding of aluminum plates
      with aluminum wire mesh and WC powder



                                                     Shigeru Tanaka1)
                                                 Kazuyuki Hokamoto2)
                                                        Shigeru Itoh2)
                                              1)Kumamoto University
        2)Shock Condensed Matter Research Center Kumamoto University



                 Shock wave and condensed matter research center
Contents


  Background and Purpose


  Shock penetration of diamond powder into aluminum plate
            Experiment
            Numerical simulation

            Conclusion


 Explosive welding of aluminum plates with aluminum wire mesh and WC powder

            Experiment
            Numerical simulation

            Conclusion


 Future works
Background and Purpose



  Background
     Many automobile component parts are made
     from aluminum alloy.
     Heat release and wear resistant materials are
     required for some automobile components.




 Purpose of this study

       Investigation of adding hard materials to increase the properties of
       aluminum using two proposed methods – experimental and numerical
       study
          Shock penetration of diamond powder into aluminum plate


            Experimental method

                                                                                Flyer plate


water                                 PMMA


  Explosive                                           Electric
                                  D
              Sample                                 Detonator


  Steel                                                             Water proof seal
                                                                    0.5mm thickness
                                             Diamond powder

                                                                 Base plate
   Explosive: SEP 5mm thickness
   (detonation velocity:7km/s, density: 1310kg/m3)
   Aluminum flyer and base plate
   (JIS: A-1050, 50x50x1.5mm)
   Diamond powder (10-20μm)
            Shock penetration of diamond powder into aluminum plate


               Production of composite material in this study




        1                                                     2
                                                 Shock wave

                                                                  Flyer plate
                                                                                Flyer plate surface


                                                                                                         Penetrated
            Flyer plate                                                                               diamond powder
                           Flyer plate surface                    Base plate

0.5mm        Air                           Diamond powder


            Base plate                                        3
                                                                     Flyer plate
                                                                                                        Penetrated
                                                                                                      diamond powder
                                                                                       separate

                                                                     Base plate
Shock penetration of diamond powder into aluminum plate


  Results                                                 50mm




                                   1.5mm




                                                                      50μm
       Top view of recovered
       flyer plate (D=30mm)                Cross sectional optical micrograph
                                                      of the sample
Shock penetration of diamond powder into aluminum plate


  Pressure calculation for explosive
             Explosive: SEP
             provided by Asahi Kasei corp.
             detonation velocity: 6970(m/s)
             detonation pressure: 15.9(GPa)
JWL(Jones-Wilkins-Lee) equation of state for SEP explosive
                                                    E
   P  A1 
     *
                exp(  R1V )  B 1     exp(  R2V ) 
         VR1 
                                 VR2 
                                                        V
 V= r 0(initial density of an explosive )/r (density of a detonation gas)
 P*: Pressure      E : specific internal energy
 A,B,R1,R2,w : JWL Parameter

                JWL parameter for explosive SEP
            A(GPa)        B(GPa)          R1            R2            w

              365          2.31          4.30          1.10         0.28
Shock penetration of diamond powder into aluminum plate


  Burn technique of explosive / CJ volume burn method

  Detonation condition was decided by the reaction rate of explosives.(=W)
  A reaction rate W was calculated by the following formula:

                        V0  V                   V0:Initial specific volume
      W 1
                       V0  Vcj                  VCJ:Specific volume of C-J state



 The Pressure P inside the grating of explosives is calculated from the
 following formula:


              P  ( 1  W )P                 *

         P*: Pressure calculated from JWL EOS
Shock penetration of diamond powder into aluminum plate


  Pressure calculation for water and aluminum



  Mie-Grümeisen equation of state for water and aluminum

       0 c 0            0 
                  2                                       P: pressure
   P                    1  2   00e
                                                          e : internal energy
      (1  s) 2                                        r0: initial density
                                                          r: density
                                                            1  0 / 


    Material constants

                      ρ(kg/m3)     C0 (m/s)
                                    0               S                Τ0
                                                                      0

       water            1000        1490           1.79             1.65
     aluminum           2710        1340           1.34               2
Shock penetration of diamond powder into aluminum plate


  Investigation of flyer velocity




                                    PMMA
                                                    Explosive



                                             30mm      Water



                               Flyer plate
Shock penetration of diamond powder into aluminum plate


  Relation between acceleration distance and flyer velocity




                       700
                       600
                       500
      Velocity (m/s)




                       400
                       300
                       200
                       100
                        0
                             0   0.5        1          1.5    2
                                       Distance (mm)
Shock penetration of diamond powder into aluminum plate


  Simplified simulation of shock powder penetration
Shock penetration of diamond powder into aluminum plate


  Conclusion

      It was realized that it is possible to make a aluminum based composite
      material by this method.
      From the numerical simulation, we could see that the particles are pushed by
      the particle which exists in a lower position.


  Problem
      This method is inapplicable to hard materials like stainless steel.


      Only few particles penetrated, while others remain between the plates.
 Explosive welding of aluminum plates with aluminum wire mesh and WC powder


   Sample constitution



                                          Cover plate
                                          Flyer plate
                                         Wire mesh
                                         Flyer plate
WC powder                                Wire mesh
                                         Base plate
                                                                          0.17mm




                    Cover plate Flyer plate   Wire mesh      Base plate    Powder
        Material    JIS:SUS304  JIS:A-1050    JIS:A-1050    JIS:A-1050       WC
         Size      80x60x0.1mm 80x60x0.1mm     100 mesh    80x60x10mm     75-100μm
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Experimental method and conditions
                                                  Electric detonator

                                 PMMA
           Water


                                         D                    Sample
                   Explosive



                                                                   Anvil



Experimental conditions
                                                  Calculated
     No.           D (mm)      Stratum                                 Powder weight (g)
                                             load pressure (GPa)
      1              10          2                   2.7                    0.5×2
      2              20          2                   1.85                   0.5×2
      3              30          2                   1.4                    0.5×2
      4              30          1                   0.95                    0.5
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Optical micrograph of recovered samples
  (When the distance, D is varied)




                          100μm                                   100μm

     No.1 (D=10mm)                               No.2 (D=20mm)
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Optical micrograph of recovered samples
  (When the layer is varied)




                               100μm                               100μm

No.3 (two layer,D=30mm)                     No.4 (single layer ,D=30mm)
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Magnified optical micrograph showing the crushed WC particles and aluminum




                                                  20μm

                              No.1 (D=10mm)
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  SEM image of fracture surface
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Investigation of pressure history




                                 PMMA
                                             Explosive


                                      10mm
                                      10mm       Water
                                      10mm
                                      10mm

                                             Measurement points
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Numerically obtained results - pressure vs time


                         3
                        2.5
       Pressure (GPa)




                         2                                      10mm
                                                                20mm
                        1.5
                                                                30mm
                         1                                      40mm
                        0.5
                         0
                              0   10   20       30   40   50
                                        Time (μs)
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Investigation of flyer velocity at 10mm




                                       10mm



                                     SUS plate (0.1mmthickness)
                                      + aluminum plate (0.1mm thickness)
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Relation between acceleration distance and flyer velocity


                     1400
                     1200
                     1000
    Velocity (m/s)




                     800
                     600
                     400
                     200
                        0
                            0   0.2   0.4        0.6      0.8   1
                                      Distance (mm)
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Simplified simulation and cross sectional view after etching



     Flyer plate
                               WC particle




                   Mesh wire
     Base plate
Explosive welding of aluminum plates with aluminum wire mesh and WC powder


  Conclusion

      Good samples were recovered using this technique.

      Particles were crushed by collision of particles. Some traces of particle pull
      out was observed.

      There is a possibility of explosive welding between plates and mesh.


  Future works
      For the purpose of improvement of thermal conductivity of aluminum,
      Large sized diamond particles and aluminum wire mesh will be applied for
      making a Al-based composite material.
Thank you for your kind attention

								
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