Poly (methyl methacrylate) (PMMA)/polycarbonate (PC) laminates have been widely used as backboards for 5G cellphones where surface aesthetics are required. For this reason, the scratch behavior of the material is of particular interest. In the present work, the scratch behavior of alternating multi-layered PMMA/PC materials was studied by progressive normal load scratch tests and finite element modeling (FEM). The experimental results showed that interfacial delamination between the PMMA and PC layers occurred after the onset of scratch damage. The detailed delamination process and related mechanisms were revealed by FEM. It was found that interfacial delamination during scratching can be divided into three successive stages: delamination initiation, delamination expansion, and delamination propagation. All stages were revealed to be dominated by shearing mode (Mode II & III) crack propagation, while opening mode (Mode I) crack propagation was not involved. Furthermore, the mechanical results demonstrated a dramatic enhancement of ductility and toughness when the number of layers was increased.

聚甲基丙烯酸甲酯 (PMMA)/聚碳酸酯 (PC) 层压板已广泛用作需要表面美观的 5G 手机的背板。出于这个原因，材料的划痕行为特别令人感兴趣。在目前的工作中，交替多层 PMMA/PC 材料的划痕行为通过渐进法向载荷划痕测试和有限元建模 (FEM) 进行了研究。实验结果表明，PMMA 和 PC 层之间的界面分层发生在划伤开始后。FEM揭示了详细的分层过程和相关机制。发现划痕过程中的界面分层可分为三个连续的阶段：分层开始、分层扩展和分层扩展。显示所有阶段都以剪切模式（模式 II 和 III）裂纹扩展为主，而不涉及打开模式（模式 I）裂纹扩展。此外，力学结果表明，当层数增加时，延展性和韧性显着增强。