A method to weaken or even eliminate segregation at grain boundaries of copper alloys

Abstract

The invention provides a method for weakening and even eliminating segregation at grain boundary of a copper alloy. The highly dense nano-particles generated in situ in a melt in the casting process are used for reducing or even eliminating the segregation at the grain boundary in the alloy from three aspects, and specifically, solute re-distribution is hindered in the solidification process, meanwhile, a heterogeneous nucleation effect is exerted to refine grains so as to shorten a segregation path and divide the segregation phase, and a diffusion channel is provided for the segregation phasecomposition element during the heat treatment process. According to the method, the micro-alloy element and nano-particles formed by the micro-alloy element are required to be provided with three conditions which comprising that the nano-phase forming elements meet the conditions that separating out in advance in the matrix melt; the crystal lattice mismatch degree of the nano-particles and a matrix is small, a remarkable crystal grain refining effect is generated through the heterogeneous nucleation effect of the nano-particles in the solidification process, and meanwhile, the potential of particle capture is enhanced; and the nano-particles have the Hamaker constants higher than those of the matrix, and the negative van der Waals force is provided for spontaneous capture of the nano-particles; and the process is simple, the cost is low, and mass production can be realized.

Description

technical field [0001] The invention relates to a method of reducing segregation at grain boundaries of alloys. Specifically, the highly dense nanoparticles generated in situ in the melt during the casting process are used to hinder the solute redistribution during the solidification process and play the role of heterogeneous nucleation to refine the grains, as well as the composition of the segregated phase during the heat treatment process. Elements provide diffusion channels. These three aspects reduce or even eliminate methods of segregation at grain boundaries in alloys. Background technique [0002] Segregation is a common problem in the alloy casting process. The appearance of this phenomenon can be explained by the theory of solute redistribution, that is, during the solidification process of metal, the solubility of solute atoms in the solid phase decreases, and they will be discharged from the solid phase. The solute atoms at the front of the interface are continu...

AI Technical Summary

Problems solved by technology

However, extreme cooling conditions are required to achieve rapid solidification, including air gun method, spin casting method, self-quenching method and atomization method, etc. However, these methods can only be applied to small-sized parts and are difficult to apply to bulk materials. In industrial production

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