Electrical current induced mechanism in microstructure and nano-indention of Al–Zn–Mg–Cu (AZMC) Al alloy thin film

In this study, the microstructural variation and nano-indention of Al-5.7Zn-2.4Mg-1.5Cu (AZMC) thin film was investigated using DC electrical current at a density of 1000 A/cm2. The results show that microstructural changes due to the electrical current involved both the solid solubility effect and enhanced diffusion. The electrical current drove the Al atoms and Cu atoms of the matrix from the cathode to the anode. After electrical current testing, precipitation phases (Al2Cu; CuMgAl2) had decomposed into the cathode matrix and MgZn phases had grown in the anode zones. Meanwhile, the current also caused the hardness of the thin film to decrease and affected both the texture and dynamic strain mechanism of nano-indention.

► Al-5.7Zn-2.4Mg-1.5Cu (AZMC) thin film has the property of precipitation hardening and excellent fracture resistance. ► The electrical current testing is a low temperature process and the electrical current effects being closely related to the microstructural characteristics and the nano-mechanics of the alloy thin film. ► This is the latest research to use the in-situ TEM nano-indenter to investigate the DC electrical current mechanism.