Tungsten Copper Liner Explosive Sintering (2/2)

Tungsten copper liner has better properties than the pure copper liner and the properties of the liner mainly depends on W-Cu composite powder preparing and sintering process. Conventional process is mechanical alloying (MA), which has high-energy ball milling with W powder and Cu powder and occur crushing – cold welding – crushing process with solid state reaction, so a uniform distribution of tungsten copper powder can be obtained. However, tungsten powder has higher hardness and difficult to be formed, which can easily be formed gravity segregation and cause the uneven distribution of liner density in a hydraulic powder metallurgy process. Currently, relevant researchers further improve the process by grain refinement.

Explosive powder sintering technology is known as shock-wave consolidation or shock-wave compaction, which uses shock-wave or detonation adiabatic compression temperature instant powder produced by high pressure powder densification and sintering. Since the explosive sintering is a transient process, the composite interface is almost no diffusion occurs. So it not only can overcome the segregation of tungsten copper, but also the grains are too late to grow up because of the transient process, the grain is fine and the structure is uniform. The experiments show that in the process of explosive sintering, oxide powder will affect the density and microstructure of compacted material blank, which requires the powder must be fully restored.

In order to ensure that the material has a good macro-structure, the need for the process parameters have higher requirements, including the packing density of the powder, the powder ratio (mass of explosive powder and compaction ratio) of explosives and explosive rate. If the powder packing density is small, medium more loose, Mach angle decreases, explosive compaction process can easily produce Mach hole; if explosive rate is too high will form Mach reflection in the central region of the blank compaction, ejection material melts, cracks and holes. Overall, tungsten copper liner explosive sintering is beneficial for removing the component segregation and area density difference, which can remarkably improve the structure, penetration depth and armor penetration.

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