CN116815009A - A multi-component complex coherent precipitation strengthened Cu-Ni-Al-Cr-Ti high temperature resistant copper alloy and its preparation method - Google Patents

Abstract

A multi-component complex coherent precipitation-strengthened Cu‑Ni‑Al‑Cr‑Ti high-temperature resistant copper alloy and a preparation method thereof, which belongs to the field of high-temperature resistant copper alloys. The mass percentage composition of the copper alloy is Cu: 58.67~64.85wt%, Ni: 26.18~28.94%, Al: 4.51~4.99wt%, Cr: 2.60~2.88wt%, and Ti: 3.03~3.35wt%. This alloy always has a multi-component complex coherent precipitation structure. The tensile strength of the alloy at room temperature is not less than 760MPa, and the tensile strength at 800°C is not less than 200MPa. Using a combination of multiple high-temperature coherent precipitation strengthening phases can improve the high-temperature properties of copper alloys in a wide temperature range.

Description

A multi-component complex coherent precipitation strengthened Cu-Ni-Al-Cr-Ti high temperature resistant copper alloy and preparation method thereof

Technical field

The invention relates to a multi-component complex coherent precipitation-strengthened Cu-Ni-Al-Cr-Ti high-temperature resistant alloy and a preparation method thereof, which belongs to the field of high-temperature resistant copper alloys.

Background technique

High-performance copper alloys are key materials used in high-speed rail contact wires, electromagnetic guns, and rocket engine combustion chambers. The current high-temperature resistant copper alloys are mainly dispersion-strengthened and precipitation-strengthened. Oxide (Al ₂ O ₃ ) dispersion-strengthened Cu alloy has a softening temperature of up to 930°C. However, due to the poor wettability of the oxide particles and the Cu melt and the large difference in specific gravity, it is easy to segregate and difficult to disperse uniformly. , as well as side reaction inclusions and other problems, resulting in extremely poor processability, so the amount of oxide added is limited, and its hardness is not higher than 160HV. In typical precipitation-strengthened Cu-Cr alloys, the Cr precipitation phase will coarsen rapidly at high temperatures, resulting in a decrease in the softening resistance of the alloy. And with the development needs of industrialization, higher requirements have been placed on the temperature resistance of materials. Service materials need to have good high-temperature strength and high-temperature stability. Due to the chaotic space occupation problem of Cu and Ni, the stability of the γ' phase in the existing single-form cubic coherent precipitation-strengthened copper alloy decreases and is easy to redissolve at high temperatures.

Contents of the invention

In order to solve the problems existing in existing alloys, the present invention intends to prepare a multi-component complex coherent precipitation-strengthened copper alloy with good high-temperature properties. The solid solution of Ti element in the γ' phase can improve the high-temperature stability of the γ' phase, while the elemental Cr phase can improve the low-temperature strength of the alloy and improve the oxidation resistance of the alloy at high temperatures.

The technical solution of the present invention is: a multi-component complex coherent precipitation-strengthened Cu-Ni-Al-Cr-Ti high-temperature resistant copper alloy. The mass percentage of the components included in the copper alloy is Cu: 58.67~64.85wt% , Ni: 26.18～28.94%, Al: 4.51～4.99wt%, Cr: 2.60～2.88wt%, Ti: 3.03～3.35wt%. This alloy always has a multi-component complex coherent precipitation structure. The tensile strength of the alloy at room temperature is not less than 760MPa, and the tensile strength at 800°C is not less than 200MPa.

The preparation method of the multi-component complex coherent precipitation-strengthened Cu-Ni-Al-Cr-Ti high temperature resistant alloy:

According to the above composition of the alloy, use high-purity metals above 4N as raw materials to prepare the alloy; use a non-consumable vacuum arc melting furnace, pass in high-purity argon gas for protection, and repeatedly smelt the prepared alloy raw materials to finally obtain an alloy with uniform composition. Ingot; perform heat treatment on the smelted alloy ingot: first perform solution treatment, maintain at a constant temperature of 1100°C for 6 hours, and then cool to room temperature in the furnace; then perform aging treatment, maintain at a constant temperature of 450°C for 4 hours, and then in the furnace After cooling to room temperature, a multi-component complex coherent precipitation-strengthened Cu-Ni-Al-Cr-Ti high temperature resistant alloy is obtained. The alloy was subjected to high-temperature tensile testing using a universal testing machine.

The beneficial effects of the present invention are:

1. The solid solution of Ti element in the γ' phase can improve the high temperature stability of the γ' phase. The elemental Cr phase is completely consistent with the matrix and γ' phase, which can improve the low-temperature strength of the alloy, reduce the diffusion rate of elements in the Cu-Cr alloy, inhibit the coarsening of the precipitated phase, thereby improving the alloy's resistance to softening, and can Improve the oxidation resistance of alloys at high temperatures.

2. The high-temperature strength of the alloy is improved by using the complex coherent precipitation of multiple components (~500nm γ' phase + ~500nm elemental Cr phase). The normal temperature strength of the alloy is higher than 760MPa. At 800°C, the alloy strength is not less than 200Mpa, much higher than existing heat-resistant copper alloys. Using a combination of multiple high-temperature coherent precipitation strengthening phases can improve the high-temperature properties of copper alloys in a wide temperature range.

Description of the drawings

Figure 1 is the SEM secondary electron image of Cu _61.76 Ni _27.56 Al _4.75 Cr _2.74 Ti _3.19 (wt.%) alloy after aging treatment. Figure 2 is the engineering stress-strain curve of Cu _61.76 Ni _27.56 Al _4.75 Cr _2.74 Ti _3.19 (wt.%) alloy at room temperature and 800°C after aging treatment.

Detailed ways

Specific embodiments of the present invention are described in detail below in conjunction with technical solutions.

Example 1: Cu _61.76 Ni _27.56 Al _4.75 Cr _2.74 Ti _3.19 (wt.%) alloy

Step 1: Alloy Preparation

According to the alloy composition Cu _61.76 Ni _27.56 Al _4.75 Cr _2.74 Ti _3.19 (wt.%), the alloy is prepared using raw materials of Cu and Al with a purity of 5N and Ni, Cr and Ti with a purity of 4N; a non-consumable vacuum arc melting furnace is used. Pass high-purity argon gas for protection, and repeatedly smelt the prepared alloy raw materials 5 times to finally obtain an alloy ingot with uniform composition; then the smelted alloy ingot is heat treated (solid solution treatment: heat preservation at 1100°C for 6 hours, and then Cool to room temperature in the furnace; aging treatment: hold at 450°C for 4 hours, then cool to room temperature in the furnace).

Step 2: Alloy structure and performance characterization

The German Bruker D8 FOCUS X-ray diffractometer and JSM-7900F field emission scanning electron microscope were used to analyze the structure and structure of the alloy. It can be determined that the alloy contains multi-scale multi-phases, and its microstructure morphology is shown in Figure 1. The UTM5504 material testing system produced in Shenzhen, China, was used to conduct tensile tests on the alloy samples at room temperature and 800°C with a nominal strain rate of 1×10 ^-4 /s. The room temperature and high temperature tensile tests were conducted according to the national standards for room temperature and high temperature tensile tests of metal materials (GB/T 228.1-2010 and GB/T 228.2-2015). The results show that the tensile strength of the alloy at room temperature is not less than 760MPa, and the tensile strength at 800°C is not less than 200MPa, as shown in Figure 2.

Claims (2)

1. A multi-component complex coherent precipitation strengthening Cu-Ni-Al-Cr-Ti high temperature resistant copper alloy is characterized in that: the copper alloy comprises the following components in percentage by mass: 58.67 to 64.85 weight percent, ni:26.18 to 28.94 percent of Al:4.51 to 4.99 weight percent, cr:2.60 to 2.88 weight percent of Ti:3.03 to 3.35 weight percent; the alloy always has a multi-component complex coherent precipitation structure, the tensile strength of the alloy at room temperature is not lower than 760MPa, and the tensile strength at 800 ℃ is not lower than 200MPa.

2. The method for preparing the multi-component complex coherent precipitation strengthening Cu-Ni-Al-Cr-Ti high temperature resistant copper alloy, which is characterized by comprising the following steps of:

using high-purity metal with the purity of more than 4N as a raw material, adopting a non-consumable vacuum arc melting furnace, introducing high-purity argon for protection, repeatedly melting the alloy raw material prepared by the alloy components according to claim 1, and finally obtaining an alloy ingot with uniform components;

carrying out heat treatment on the smelted alloy ingot: firstly, carrying out solution treatment, keeping the temperature at 1100 ℃ for 6 hours, and then cooling to room temperature in a furnace; and then aging treatment is carried out, the temperature is kept for 4 hours at the constant temperature of 450 ℃, and then the alloy is cooled to room temperature in a furnace, so as to obtain the multi-component complex coherent precipitation strengthening high-temperature resistant alloy.