High-performance, low-cost nanoporous alloy actuators by one-step dealloying of Al-Ni-Cu precursors

Nanoporous metal-based actuators show advantages over conventional piezoelectric ceramics and conducting polymers, but are mainly limited to noble metals. Herein, we design a series of ternary Al-Ni-Cu alloys with variable Ni/Cu ratios to investigate their dealloying behaviors as well as electrochemical actuation performances. The change of the Ni/Cu ratio influences the microstructure and phase constituent of the as-cast Al-Ni-Cu alloys. Specially, an Al-3(Ni, Cu)(2) phase is identified in all the Al-Ni-Cu alloys, and its amount and composition alter with the Ni/Cu ratio. Furthermore, the corrosion-resistant Al-3(Ni, Cu)(2) phase significantly affects the dealloying behaviors of the ternary Al-Ni-Cu precursors. Additionally, the as-dealloyed Al-Ni-Cu alloys show good electrochemical actuation performance, which is associated with the existence of efficient nanoporous (np) components (np-Cu and np-Ni). The largest strain amplitude and strain rate could reach up to 0.9% and 6.6 x 10(-4) s(-1), respectively. Compared with noble metal-based actuators, the large strain amplitude and strain rate, as well as the lower material cost, make nanoporous Al-Ni-Cu alloy a potential actuation material for practical applications.

Automated summary

In this study, a series of ternary Al-Ni-Cu alloys with variable Ni/Cu ratios were designed to investigate their dealloying behaviors and electrochemical actuation performances. The change in Ni/Cu ratio was found to influence the microstructure and phase constituent of the alloys. Nanoporous Al-Ni-Cu alloys showed good electrochemical actuation performance and potential for practical applications.