Microstructures of electron beam welding joint of CNTs/Al composites

Carbon nanotube（CNT） reinforced aluminum metal matrix composites were welded by electron beam welding and the microstructures of welded joints were investigated.The result showed that the interfacial reaction happened between the CNTs and Al matrix,which resulted in producing brittle Al₄C₃ compounds in electron beam welds.The extent of interfacial reaction varies gradually in the depth and width direction.The length of the reactants Al₄C₃ became short duo to the temperature gradient in the molten pool.The quantity and size of Al₄C₃ compounds increased with the increase of beam current and the decrease of welding speed in the middle zone of weld.However,no needle-like phase Al₄C₃ was observed in HAZ.