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

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 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 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)

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

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

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)

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

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

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

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

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

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

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)

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)

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

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

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.

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)

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

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

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.

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