Exceptional strength-ductility synergy achieved by spinodal decomposition in a high Cu content high-entropy alloy

Abstract

As the marine industry progresses, copper-containing metallic materials that possess both high strength and ductility are demanding. Traditional copper alloys used in marine environment face challenges regarding inadequate strength and corrosion resistance. In the present work, cold rolling and subsequent high-temperature annealing processes were employed to the Cu1.2NiMnFe0.5Cr0.5Al0.2 high-entropy alloy. This alloy exhibited remarkable mechanical properties, including a yield strength (YS) of 530 MPa, ultimate tensile strength (UTS) of 913 MPa, and a relatively high fracture elongation (EL) of 37.7%. After subsequent aging treatment at 400 °C, spinodal decomposition occurred within the matrix, leading to enhanced strength. The decomposed microstructure was comprehensively characterized, and the strengthening mechanism was analyzed. Notably, the sample aged for 6 h exhibited a YS of 701 MPa and an EL of 21.8%. The present HEAs exhibit superior mechanical properties compared to traditional copper alloys and other Cu-containing HEAs, when considering both strength and ductility. Furthermore, these alloys demonstrated exceptional corrosion resistance and a favorable copper ion release rate in 3.5 wt% NaCl solution. This work introduces an innovative class of advanced alloys and offers a strategic approach to alloy design for marine applications.

Keywords

• High-entropy alloys
• Spinodal decomposition
• High strength and ductility
• Copper alloys
• Marine materials