Effect of heat treatment on microstructure and mechanical properties of Cu–6.9Ni–2.97Al–0.99Fe–1.06Mn alloy

Abstract

The effect of heat treatment on the mechanical properties and microstructures of Cu–6.9Ni–2.97Al–0.99Fe–1.06Mn alloys was investigated. The results show that the microstructure of the as-cast alloy mainly consists of an alpha-copper matrix and γ-phase Ni3Al particles. The microstructure of the alloy after solution treatment at 950°C for 2 h is a single-phase alpha-copper supersaturated solid solution and the second-phase strengthening disappears. After ageing treatment at 550°C for 6 h, the γ-phase particles are fully precipitated, and the mechanical properties of the alloy are significantly improved. The tensile strength is increased from 305 to 588 MPa. Quasi-cleavage fracture with shallow dimples appeared in the Cu–6.9Ni–2.97Al–0.99Fe–1.06Mn alloy aged at 550°C for 6 h.

TITANIUM ADDITION AND AGEING INFLUENCE ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Cu-10Ni ALLOY

“…Cu-Ni alloy is a simple binary alloy. High strength Cu-Ni alloys can be realised through additional alloying elements to its binary alloys [9,10,11]. Cu-Ni alloys containing other alloying elements outperform single binary Cu-Ni alloys in terms of mechanical properties, alloy's ability to resist corrosion in aqueous environments, low sensitivity to hydrogen embrittlement, and good anti-biofouling capabilities [8].…”

“…Increasing the Ni contents and alloying compositions in Cu-Ni alloys, the number of δ-Ni 2 -x strengthening precipitates can be increased, resulting in an increase in the alloy's tensile strength [16,17]. The various third alloying elements includes Cr, Al, Mg, Ag, Si, Ti, P, Zn and Fe [9,11,17,18]. Due to their active chemical capabilities, titanium can produce second phases with other elements when used as a micro-alloying component in copper alloys [20].…”