Method for improving strength and conductivity of smelted and cast Cu-Cr-Nb alloy

Abstract

The invention relates to a method for improving strength and conductivity of a smelted and cast Cu-Cr-Nb alloy, and belongs to the field of copper alloy materials. The alloy is mainly prepared from Cu, Cr, Nb and M, the proportion of Cr is 0.5-2.5 wt.%, the proportion of Nb is 0.1-1.0 wt.%, the proportion of M is 0.1-0.50 wt.%, and the balance is copper. The M is composed of at least four elements of RE, Ag, B, P, Si, Ca, Li, Mg, Ti, Fe, Zr and Mn, and the RE is selected from at least one of Ce, La, Y, Pr, Nd, Sm, Sc, Gd and Dy. According to the method, the microalloying element M is added into the alloy, and the large-size high-strength high-conductivity Cu-Cr-Nb-M alloy which is fine in structure and uniform in component is prepared through smelting, casting and thermomechanical treatment. A metal mold is used as an inner mold and surrounds a cooling pipe, a sand mold is used as a special combined mold of an outer mold, and the melt solidification rate is increased through cooling water. By means of the combined action of M microalloying, rapid solidification and thermomechanical treatment, the structure of the alloy is regulated and controlled, the performance of the alloy is improved, a multi-scale multi-phase, fine-grain, sub-grain and dislocation entangled microstructure is obtained, direct casting forming of the large-size Cu-Cr-Nb alloy is achieved, and synchronous improvement and good matching of the strength and the electric conductivity are achieved. The process is simple, the production cost is low and the application prospect is good.

Description

technical field [0001] The invention relates to a method for improving the strength and electrical conductivity of a smelted and cast Cu-Cr-Nb alloy, which belongs to the field of copper alloy materials. Background technique [0002] Cu-Cr-Nb alloys have excellent mechanical properties, electrical and thermal conductivity, and structural stability, and have broad application prospects in rocket engines and UHV switches. Cu-Cr-Nb alloy matrix Cu has a large difference in melting point between the alloy components Cr and Nb, the melting temperature is high, and the alloy melting and alloying are difficult. At the same time, during the casting solidification process, Cr and Nb preferentially form a coarse intermetallic compound Cr with high melting point and high hardness. 2 The second phase of Nb leads to uneven composition and structure, which is difficult to effectively control through subsequent deformation processing and heat treatment, which reduces the performance of th...

AI Technical Summary

Problems solved by technology

Chinese patents 201710736572.X and 201710737221.0 disclose a Cu-Cr-Nb alloy smelting casting and heat treatment preparation method. The content of Cr in the prepared alloy is ≤1.5wt.%, the content of Nb is ≤0.5wt.%, and the electrical conductivity is about 82.5% IACS, hardness about 135HB, no strength data reported

[0004] Aiming at the deficiencies of the prior art, the present invention provides a high-strength and high-conductivity copper alloy and its manufacturing method. The alloy composition is optimized through microalloying, a specially designed casting mold is used to obtain a suitable cooling rate, and large-sized copper alloys are prepared by melting and casting. For Cu-Cr-Nb alloy materials, the matching deformation heat treatment is adopted to further control the microstructure of the alloy to obtain high-performance Cu-Cr-Nb alloys. The process is simple, and there is no relevant report so far.

Images