Fabrication of W-Cu composite by shock consolidation of Cu-coated W powders

Nearly fully dense (>98% theoretical density) W-Cu composites, using Cu-coated W powders, have been fabricated by shock consolidation. The composites are free of cracks, and shows homogenous distribution of W and a Cu network structure. The high density is obtained under relatively low shock pressure of ∼1 GPa without preheating; because the sintering is only related to Cu-Cu sintering. The thermal (thermal conductivity) and mechanical (quasi-static compression and hardness) properties of the composites are measured experimentally. It is found that the bonding of W and Cu is determined during the electroless coating process and increasing in shock intensity doesn't improve the bonding strength. Inappropriate coating process and subsequent oxidation leads to the weak bonding and inferior thermal performance in this work. The Cu network as a continuous phase significantly influences the mechanical response and the weak bonding strength between W and Cu leads to axial splitting as a primary failure mode. After increasing the shock intensity, nano-sized W particles are formed at the center due to the particle crushing and jet penetration. The fragmentation of W particles decreases the hardness at the center because good bonding is formed due to the high surface energy of nano-sized particle.