1. 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

2. 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

3. Background and Purpose
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

4. Shock penetration of diamond powder into aluminum plate
Experimental method
Flyer plate
Water proof seal 0.5mm thickness
This figure shows schematic illustration of method for processing using underwater shock wave. Experiment was conducted in water. Explosive is shaped in 5mm thickness. Explosive was pasted on PMMA plate. Explosive used in this research is SEP. the detonation velocity is about 7000m/s, density is 1310kg/m3. The sample was put on the steel anvil. The distance from explosive to sample is shown as D. Initiation was conducted by NO.6 electric detonator. Generated shock wave is converted to underwater shock wave. Under water shock wave act on the sample. The detail of sample is shown right figure. The sample is made up of tow metal plates, diamond powder and water seal. Upper plate is flyer plate. Lower plate is base plate. Diamond powder is put on base plate. Water seal has 0.5mm thickness. Thus, the gap between the plates is 0.5mm. When shock wave passes through the sample, flyer plate will be accelerated during the gap, and It will be collided with diamond.
Diamond powder
Base plate
(detonation velocity:7km/s, density: 1310kg/m3)
Explosive: SEP 5mm thickness
Aluminum flyer and base plate
(JIS: A-1050, 50x50x1.5mm)
Diamond powder
(10-20μm)

5. Shock penetration of diamond powder into aluminum plate
Production of composite material in this study 2 1
I explain about production of composite in this study. Fist two metal plates are placed like this. Upper plate is flyer plate, lower plates is base plate. Diamond powder is placed on base plate. Explosive is exploded upper place. Generated shock wave acts on flyer plate.
When shock wave passes through the flyer plate. Flyer plate is accelerated by shock wave and collided with diamond and base plate. Metal plate surface is become soft by high pressure. Diamond particles are penetrated into flyer and base plate. Flyer plate and base plate are separated by reflection wave. Diamond rich layer may be made at the flyer and base plates surface. Therefore surface improvement of wear resistant will be expected. 3

6. Shock penetration of diamond powder into aluminum plate
Results
50mm
1.5mm
This photograph shows top view of recovered sample. We can see that the micro diamond was buried in the flyer plate. This photograph shows cross sectional view cutting like figure. Black points show penetrated diamond particles. We can see that the diamond particles exist not only surface but also inside.
50μm
Top view of recovered flyer plate (D=30mm)
Cross sectional optical micrograph of the sample

7. 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
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
0.28
1.10
4.30
2.31
365 w R2 R1
B(GPa)
A(GPa)

8. 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：Initial specific volume
VCJ：Specific volume of C-J state
The Pressure P inside the grating of explosives is calculated from the following formula:
P*: Pressure calculated from JWL EOS

9. Shock penetration of diamond powder into aluminum plate
Pressure calculation for water and aluminum
Mie-Grümeisen equation of state for water and aluminum
P: pressure
e : internal energy
r0: initial density
r: density
Material constants

10. Shock penetration of diamond powder into aluminum plate
Investigation of flyer velocity
PMMA
Explosive
30mm
Water
Flyer plate

11. Shock penetration of diamond powder into aluminum plate
Relation between acceleration distance and flyer velocity

12. Shock penetration of diamond powder into aluminum plate
Simplified simulation of shock powder penetration
It's not exactly that simple.

13. 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.

14. Explosive welding of aluminum plates with aluminum wire mesh and WC powder
Sample constitution
Base plate
Flyer plate
Wire mesh
Cover plate
WC powder
0.17mm

15. Explosive welding of aluminum plates with aluminum wire mesh and WC powder
Experimental method and conditions
Experimental conditions

16. 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)

17. Optical micrograph of recovered samples
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)

18. 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)

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

20. Investigation of pressure history
Explosive welding of aluminum plates with aluminum wire mesh and WC powder
Investigation of pressure history
PMMA
Explosive
10mm
Water
10mm
This simulation is the same as before and Indicates measurement points for pressure by red lines.
10mm
10mm
Measurement points

21. Numerically obtained results - pressure vs time
Explosive welding of aluminum plates with aluminum wire mesh and WC powder
Numerically obtained results - pressure vs time
This is the numerical result of pressure vs time at different distance.

22. Investigation of flyer velocity at 10mm
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)

23. Explosive welding of aluminum plates with aluminum wire mesh and WC powder
Relation between acceleration distance and flyer velocity

24. Simplified simulation and cross sectional view after etching
Explosive welding of aluminum plates with aluminum wire mesh and WC powder
Simplified simulation and cross sectional view after etching
Flyer plate
WC particle
It's not exactly that simple.
Smoothed Particle Hydrodynamics
analyze a phenomenon(現象を解析する)
Mesh wire
Base plate

25. 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.

26. Thank you for your kind attention