Fabrication of Cu-riched W-Cu composites by combustion synthesis and melt-infiltration in ultrahigh-gravity field

Unadulterated Cu-riched W-Cu composites of W27-Cu73, W34-Cu66, W40-Cu60, W49-Cu51 and W56-Cu44 have been prepared by a novel method called combustion synthesis and melt-infiltration in ultrahigh-gravity field, of which W27-Cu73 and W34-Cu66 showed good ductility and W40-Cu60, W49-Cu51 and W56-Cu44 were brittle. In this technique, Cu melt accompanied with a great amount of heat was produced by thermit reaction and infiltrated into W-Cu powder bed. When the powder bed was Cu-riched powder bed such as W50-Cu50 or W60-Cu40, Cu melt would go through the powder bed, reach the bottom of the graphite crucible and then form a heat dissipation channel. Thus the cooling rate was so fast that the product was mixed up with impurity. The problem can be solved by putting some W powders under W50-Cu50 or W60-Cu40 powder bed to prevent the formation of heat dissipation channel.