Nucleation and growth of γ-Fe precipitate in Cu-2%Fe alloy aged under high magnetic field

Abstract

Cu-2wt%Fe alloy, an inexpensive candidate for a high strength conductor, depends for its conductivity on the precipitation of Fe. We applied an external 12 T high magnetic field (HMF) during ageing treatment of this alloy in order to study the resulting γ-Fe precipitation on the electrical conductivity. When the alloy was aged at 450 °C for up to 16 hrs, coherent γ-Fe precipitates formed within the Cu matrix. Between the γ-Fe precipitates and the Cu matrix, the lattice misfit was 1.4%±0.7% and the angle between closed packed planes was about 0.3. These γ-Fe precipitates became semi-coherent with the surrounding Cu matrix in samples aged at 700 °C for over 0.5 h. HMF made insignificant contributions to both the morphology and the volume fraction of γ-Fe at 450 °C. At 700 °C, however, HMF promoted a transformation from coherent to semi-coherent γ-Fe precipitates. Applying HMF during ageing at 700 °C increased electrical conductivity. HMF had little influence on the nucleation of γ-Fe precipitation. We applied the Lifshitz-Slyozov-Wagner (LSW) formula to the coarsening data of the precipitates and determined that HMF increased the diffusion coefficient of Fe in Cu and promoted the growth of γ-Fe precipitation out of the Cu matrix.

Co-Precipitation, Strength and Electrical Resistivity of Cu–26 wt % Ag–0.1 wt % Fe Alloy

“…Fe precipitates with diameters of ~5 nm were observed after ageing at 550 °C in Fe-doping alloy ( Figure 6 a). Our previous result indicated that Fe precipitates and the Cu matrix had a cube-on-cube orientation relationship [ 21 ]. Magnetization curves of both the Fe-free alloy and the Fe-doping alloy after a heat treatment, aged at 550 °C for 4 h, are shown in Figure 6 b.…”

“…This Cu–Fe alloy also serves as a good candidate for conductive materials, because of the low costs of iron compared to other insoluble elements [ 6 , 20 , 21 ], as well as its excellent mechanical properties [ 22 , 23 ]. According to the Cu–Fe phase diagram [ 24 ], the maximum solubility of iron in copper is 4.1 wt %, and its minimum solid solubility at room temperature is significantly lower than 1 wt %.…”

“…According to the Cu–Fe phase diagram [ 24 ], the maximum solubility of iron in copper is 4.1 wt %, and its minimum solid solubility at room temperature is significantly lower than 1 wt %. It is possible to precipitate Fe out of a Cu matrix, and enhance strength and electrical conductivity [ 21 , 25 , 26 ]. However, the application of the Cu–Fe alloys has been limited, because serious composition segregation takes place during solidification [ 27 ].…”

Influence of External Static Magnetic Fields on Properties of Metallic Functional Materials

“…However, the increase in the strength is generally accompanied by a decrease in the electrical conductivity, and vice versa [38][39][40][41][42]. Our group applied SMFs to control the microstructures during the solidification process of the alloys in order to improve the tradeoffs between strength and electrical conductivity [43][44][45][46]. Figure 2 shows the comparison of Cu-Fe alloys by using SMFs in different processes.…”

Effect of aging on properties and nanoscale precipitates of Cu-Ag-Cr alloy

“…Sometimes they can also be used as bacteriostatic biomaterials [1][2][3][4][5][6][7][8]. Microalloying is usually used by material researchers to maintain the alloy's high electric conductivity and mechanical properties [9,10]. The high strength of alloys is due to nanoscale precipitates in the copper matrix during the aging process.…”