Abstract
The volume fractions and morphology of pre-cipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous pre-cipitates,are important for the application of the alloy.This study employed hardness and electrical conductivity tests,transmission electron microscopy(TEM),atom probe tomography(APT),and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuous β'-Cu4Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuous β-Cu4Ti precipitates along the grain boundaries,resulting in Cu-Ti alloys with high yield strength and good electrical conductivity.The results showed that the continuous precipitation of β'-Cu4Ti was accelerated by the Mg additions,which reduced the supersaturation of the matrix,thereby reducing the chem-ical driving force for the discontinuous precipitates.On the other hand,Mg additions increased the mismatch between the discontinuous β-Cu4Ti precipitates and matrix,decreased the nucleation rate of the discontinuous precip-itates,and increased the spacing of the discontinuous pre-cipitation layer,resulting in a lower growth rate of the discontinuous precipitates.Therefore,the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.
基金项目
Technological Innovation 2025 & Major Special Project of Ningbo(2021Z084)
Technological Innovation 2025 & Major Special Project of Ningbo(2020Z039)
NETL
NSTL
万方数据