Microstructure and properties of high-conductivity, super-high-strength Cu–8.0Ni–1.8Si–0.6Sn–0.15Mg alloy

Abstract

A high-conductivity and super-high-strength alloy, Cu-8.0Ni-1.8Si-0.6Sn-0.15Mg, has been developed. The processing conditions of the alloy have been investigated. The evolution of microstructure of the alloy on aging has been examined by transmission electron microscopy. The processing condition giving the highest hardness and good electrical conductivity is as follows: solution treatment at 970 C for 4 h, cold rolling to 60% reduction, and aging at 500 C for 30 min. The processed alloy has an average tensile strength of 1180 MPa, 0.2% proof strength of 795 MPa, elongation of 2.75%, and average electrical conductivity of 26.5% International Annealed Copper Standard (IACS). Orthorhombic Ni 2 Si precipitates are responsible for the age-hardening effect. The orientation relationship between the precipitates and the matrix is (110) m ==(211) p and 001 ½ m == 01 1 ½ p . DO 22 ordering together with spinodal decomposition also contributed to the hardening.

Phase transformations behavior in a Cu–8.0Ni–1.8Si alloy

“…After surface defects were removed, the ingot was homogenized at 930 • C for 24h in a N2 + H2 atmosphere and subsequently rolled at 900 • C in a N2 atmosphere, reducing the ingot thickness from 20 mm to 4 mm. In our previous research, we have investigated the solution-treatment temperature for Cu-8.0Ni-1.8Si-0.6Sn-0.15Mg alloy systematically and the results indicate that 965 • C is a suitable solution-treatment temperature for high solute concentrations Cu-Ni-Si alloys [10]. Therefore, the resultant strip was solution-treated at 965 • C for 6 h in a N2 + H2 atmosphere followed by quenching into isothermal bath with 0925-8388/$ -see front matter © 2010 Elsevier B.V. All rights reserved.…”

“…Alloying is an effective method to conduct new Cu-based materials with high strength and good electrical conductivity [8,9]. Cu-Ni-Si-based alloys with high solute concentrations have super high strength and good conductivity, which has a good prospect for substituting for toxic Cu-Be alloys [10]. However, most previous studies on the phase transformation investigated the precipitation process for the Cu-3.1Ni-1.4Si alloys with low solute concentrations [11].…”

“…However, most previous studies on the phase transformation investigated the precipitation process for the Cu-3.1Ni-1.4Si alloys with low solute concentrations [11]. At least four different kinds of precipitation products have been observed by different investigators: DO 22 ordered structure [10,12], ␤-Ni 3 Si precipitates [13], ␦-Ni 2 Si precipitates [14][15][16][17][18], and ␥-Ni 5 Si 2 precipitates [19]. Thus, to say the least, the overall transformation kinetics of Cu-Ni-Si alloys appears to be as complex as other ternary copper alloys [20].…”

The Effect of Severe Plastic Deformation and Heat Treatment on CuCrZr Alloys

“…CuCrZr alloys are classified as precipitation-hardened (PH) materials processed by heat treatment which are traditionally used in applications where a combination of high mechanical strength, heat resistance and electrical (or thermal) conductivity is demanded (electrodes for point welding, heat exchangers, etc.) [21][22][23]. It has to be mentioned that CuCrZr alloys are considered as a prime material for fusion reactors (international thermonuclear experimental reactor -ITER) [24,25].…”

Deformation Behavior and Microstructure Evolution of the Cu-2Ni-0.5Si-0.15Ag Alloy During Hot Compression

“…Among these alloys, Cu-Ni-Si has become a research focus due to its high strength and hardness, good processing properties, and modest electrical conductivity. [2][3][4][5][6][7][8][9][10][11][12][13] Cu-Ni-Si alloy is one of the age-hardening alloys. Corson had been the first to find the hardening behavior of this alloy in 1927, and attributed this age-hardening behavior to the precipitation of the d-Ni 2 Si phase.…”