Atomic Observation of the Al2Cu Interface in Cu/Al Shaped Charge Liners

Abstract Shaped charge liners have recently received a lot of attention due to their exceptional properties, particularly copper–aluminum (Cu–Al) bimetal liners which cause larger penetration than copper liners. However, inevitably high brittle compositions exist along the interface such as Al 2 Cu and Al 4 Cu 9 which induce low plasticity to negatively influence the performance. Until now, the interface structure between these compositions and Cu/Al has seldom received attention. In this paper, the interface between Al 2 Cu and Cu/Al is depicted and studied on atomic level. Aberration‐corrected scanning transmission electron microscopy (STEM) and energy dispersive spectrometry (EDS) reveal that the Al 2 Cu are the main compositions of Al x Cu along Cu/Al interface. Importantly, the interface structure of Al 2 Cu–Cu and Al 2 Cu–Al is demonstrated, where the Al 2 Cu–Cu interface has a transition region showing polycrystalline, while the Al 2 Cu–Al interface exhibits a sharp boundary which can form a 5 nm width co‐exist area in which Al 2 Cu and Al both exist without any mismatch or dislocation. The findings certify the discrepant atomic structure in the interface which can help understanding the connection style of highly brittle compositions and Cu/Al. This phenomenon has potential value in understanding the Cu/Al liner's performance and Cu/Al alloys in the future.