>> “Seamless joining of carbon fiber and aluminum using ultrasonic additive manufacturing (UAM)” appeared in Composite Structures

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Various methods have been reported to join carbon fiber reinforced polymer (CFRP) composites with aluminum alloy (AA), with strengths ranging from 13 MPa to 112 MPa. This paper presents a new method for joining carbon fiber composites and metals using ultrasonic additive manufacturing (UAM). Although UAM is a metal 3D printing process, it is applied here to produce continuous CF-AA transition joints that can have uniform thickness across the CF and AA constituents. Joint strength is achieved by mechanical interlocking of CF loops within the AA matrix; tensile tests demonstrate that UAM CFRP-AA joints reach strengths of 129.5 MPa. The dry CF fabric extending from these joints can be laid up and cured into a CFRP part, whereas the AA can be welded to metal structures using traditional metal welding techniques – hence their designation as “transition joints.” This approach enables the incorporation of CFRP parts into structures without requiring modifications to existing metal welding infrastructure. Two failure modes, CF tow failure and AA failure, have been identified. It is shown that the joint failure mode can be designed for maximum strength or maximum energy dissipation by adjusting the ratio of embedded CF to AA matrix.

 

H. GUO, M.B. GINGERICH, L.M. Headings, R. Hahnlen, and M.J. Dapino, “Seamless joining of carbon fiber and aluminum using ultrasonic additive manufacturing (UAM),” Composite Structures. Vol. 2018,180-188, 2019.