阅读说明：本技术 一种耐腐蚀高锰铝青铜合金及其制备方法 (Corrosion-resistant high-manganese aluminum bronze alloy and preparation method thereof ) 是由 段宗伟 张鑫 邵海洋 陈洋洋 冷志剑 费江 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种耐腐蚀高锰铝青铜合金及其制备方法,该铝青铜合金的重量百分比组成包括：7.4～9.4%的Al、0.5～5%的Fe、0.5～5%的Ni、10.1～15%的Mn,余量为Cu和不可避免的杂质；该铝青铜合金的微观组织主要由α相、β相、γ-(2)相和k相组成；在该铝青铜合金截面上的微观组织中,所述的α相的面积占比为75～85%,所述的k相的数量≥1×10～(4)个/mm～(2)；该铝青铜合金可实现抗拉强度≥900MPa,屈服强度≥700MPa,延伸率≥2%,硬度HV5≥240,在pH值=3的酸性气氛环境下120h不发生腐蚀,耐腐蚀性能优异,综合性能好。该铝青铜合金可用作液压缸内壁的堆焊材料,其优异的耐腐蚀性能可有效提高液压缸的使用寿命。(The invention discloses a corrosion-resistant high-manganese aluminum bronze alloy and a preparation method thereof, wherein the aluminum bronze alloy comprises the following components in percentage by weight: 7.4-9.4% of Al, 0.5-5% of Fe, 0.5-5% of Ni, 10.1-15% of Mn, and the balance of Cu and inevitable impurities; the microstructure of the aluminum bronze alloy mainly comprises alpha phase, beta phase and gamma phase 2 Phase and k phase composition; in the microstructure of the aluminum bronze alloy section, the area ratio of the alpha phase is 75-85%, and the number of the k phase is more than or equal to 1 multiplied by 10 4 Per mm 2 (ii) a The aluminum bronze alloy can realize that the tensile strength is more than or equal to 900MPa, the yield strength is more than or equal to 700MPa, the elongation is more than or equal to 2%, the hardness HV5 is more than or equal to 240, the corrosion does not occur in 120h under the acidic atmosphere environment with the pH value =3, the corrosion resistance is excellent, and the comprehensive performance is good. The aluminum bronze alloy can be used as a surfacing material for the inner wall of a hydraulic cylinder and has excellent resistanceThe corrosion performance can effectively prolong the service life of the hydraulic cylinder.)

1. The corrosion-resistant high-manganese aluminum bronze alloy is characterized by comprising the following components in percentage by weight: 7.4-9.4% of Al, 0.5-5% of Fe, 0.5-5% of Ni, 10.1-15% of Mn, and the balance of Cu and inevitable impurities;

the microstructure of the aluminum bronze alloy mainly comprises alpha phase, beta phase and gamma phase₂Phase and k phase composition; in the microstructure of the aluminum bronze alloy section, the area ratio of the alpha phase is 75-85%, and the number of the k phase is more than or equal to 1 multiplied by 10⁴Per mm²。

2. The corrosion-resistant high manganese aluminum bronze alloy according to claim 1, wherein said k-phase has an average grain size of 1.0 μm or less.

3. The corrosion resistant high manganese aluminum bronze alloy according to claim 1, wherein said k-phase comprises the following intermetallic compounds: AlFe, AlFe₃、Ni₂MnAl and Al₅Ni₃Mn₂。

4. The corrosion-resistant high-manganese aluminum bronze alloy according to claim 1, wherein the aluminum bronze alloy comprises, in weight percent, Mn, Al and Fe in amounts that: Mn/(Al + Fe) is more than or equal to 0.9 and less than or equal to 1.6.

5. The corrosion-resistant high-manganese aluminum bronze alloy according to claim 1, wherein the aluminum bronze alloy further comprises 0.001 to 2% by weight of at least one element selected from the group consisting of Cr, Ti, Zr, Si, Co, P, B, Mg, Ag and RE.

6. The corrosion-resistant high-manganese aluminum bronze alloy according to claim 1, wherein the aluminum bronze alloy has a tensile strength of 900MPa or more, a yield strength of 700MPa or more, an elongation of 2% or more, a hardness HV5 of 240 or more, and does not corrode for 120 hours in an acidic atmosphere environment with a pH of 3.

7. The method of making a corrosion resistant high manganese aluminum bronze alloy according to any of claims 1 to 6, comprising the steps of:

(1) taking the raw materials according to the proportion;

(2) putting the prepared raw materials into a smelting furnace, smelting at 1250-1350 ℃, and performing semi-continuous casting at 1150-1270 ℃ after melting to obtain an ingot;

(3) carrying out hot extrusion on the obtained cast ingot to obtain an extrusion blank, wherein the extrusion temperature is 700-800 ℃, and the extrusion ratio is 150-350;

(4) stretching and annealing the obtained extrusion blank on line;

(5) and (5) repeating the step (4) for a plurality of times until the required diameter of the finished product is achieved.

8. The method for preparing the corrosion-resistant high-manganese aluminum bronze alloy according to claim 7, wherein in the step (4), the single-pass drawing processing rate is less than 30%; the on-line annealing temperature is 500-850 ℃, and the cooling mode is water cooling.

Technical Field

The invention belongs to the technical field of copper alloys, and particularly relates to a corrosion-resistant high-manganese aluminum bronze alloy with excellent corrosion resistance and a preparation method thereof.

Background

In recent years, with the continuous development of science and technology in China, a hydraulic system is used as an important system for transmitting power and motion and is widely applied to industries such as national defense and military industry, machinery, coal and the like. The hydraulic cylinder is an important actuating element of a hydraulic system, the service life of the hydraulic cylinder directly influences the service life of the whole hydraulic system, and the corrosion resistance of the hydraulic cylinder has a critical influence on the service life of the hydraulic cylinder. The hydraulic cylinders are typically made of carbon alloy steel, and the hydraulic medium is often oil, emulsion, water, etc., which cause various degrees of corrosion to the carbon alloy steel.

In order to prolong the service life of the hydraulic cylinder, aluminum bronze alloy is often overlaid on the inner wall of the hydraulic cylinder to improve the corrosion resistance and the wear resistance of the hydraulic cylinder. Although the existing aluminum bronze alloy has high strength and high hardness, the improvement effect on the service life of a hydraulic cylinder is limited, the existing aluminum bronze alloy is difficult to bear the corrosion of various media, and the requirement on higher corrosion resistance cannot be met. The method has important significance for effectively prolonging the service life of the hydraulic cylinder and further improving the performance, particularly the corrosion resistance, of the aluminum bronze alloy.

Disclosure of Invention

The invention aims to solve the technical problem of providing a corrosion-resistant high-manganese aluminum bronze alloy with excellent corrosion resistance and a preparation method thereof aiming at the defects of the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows: the corrosion-resistant high-manganese aluminum bronze alloy comprises the following components in percentage by weight: 7.4 to 9.4% of Al, 0.5 to 5% of Fe, 0.5 to 5% of Ni, 10.1 to 15% of Mn, and the balance of Cu and inevitable impurities.

The high manganese aluminum bronze alloy is added with 7.4-9.4% of Al. The addition of Al element can improve the strength, hardness and wear resistance of the alloyCorrosion resistance and high temperature plasticity. When the Al content is less than 7.4%, only alpha-phase structure exists in the alloy, and the alloy has high plasticity and toughness and is easy to form and process, but has low hardness and strength and poor wear resistance. Along with the increase of the Al content, the beta phase appears in the alloy at high temperature to form (alpha + beta) dual-phase aluminum bronze alloy, and during the cooling process of the alloy, the k phase is separated out from the microstructure of the alloy, meanwhile, a part of the beta phase is converted into the alpha phase, and a part of the beta phase is converted into (alpha + gamma) phase₂) Leaving a small amount of beta-phase unchanged, wherein the k-phase, gamma-phase₂The phases are beneficial to increasing the strength and the hardness of the alloy. When the Al content is more than 9.4%, an excessive amount of gamma may be formed₂And the plasticity, toughness and corrosion resistance of the alloy are obviously reduced. Therefore, the Al content is controlled to be 7.4-9.4%.

The high manganese aluminum bronze alloy is added with 0.5-5% of Fe. The solubility of Fe in the aluminum bronze alloy is very low, and if the Fe is added excessively, needle-shaped FeAl is formed₃The mechanical property and the corrosion resistance of the alloy are reduced, so that the content of Fe in the alloy is not more than 5%. Fe can slow down the diffusion speed of atoms in the aluminum bronze alloy and increase the stability of beta phase, thereby inhibiting the self-annealing phenomenon causing the alloy to become brittle and greatly reducing the brittleness of the alloy. Proper amount of Fe can also play a role in refining aluminum bronze casting structure and recrystallization grains, and the mechanical property of the aluminum bronze alloy is improved. The invention controls the Fe content at 0.5-5%, and preferably 1-3%.

The high manganese aluminum bronze alloy is added with 0.5-5% of Ni. The addition of Ni can change the alpha phase and the (alpha + gamma)₂) The proportional relation of phases, the alpha phase region is enlarged, and the gamma is controlled₂The proportion of the phases ensures that the alloy can prevent excessive precipitation of gamma-gamma while improving the strength and the hardness₂Thereby avoiding the increase of the brittleness and the reduction of the toughness of the alloy. Further, Ni element solid-dissolved in the α phase can refine the α phase crystal grains. In the present invention, the Ni content is controlled to 0.5 to 5%, and more preferably 1 to 3%.

10.1-15% of Mn is added into the high-manganese aluminum bronze alloy, and Mn element plays roles in deoxidation and solid solution strengthening and is transformed into beta → alpha in eutectoid reaction+γ₂Significant reduction of gamma in the process₂The precipitation of the phase effectively inhibits the slow cooling brittleness of the aluminum bronze. Meanwhile, the addition of Mn is beneficial to the generation of alpha phase and k phase, thereby playing the roles of refining crystal grains and improving the mechanical properties of the alloy, such as corrosion resistance, wear resistance and the like. When the Mn content exceeds 10.1%, some Al-rich Al appears in the k phase₅Ni₃Mn₂Phase, Al-rich Al₅Ni₃Mn₂The generation of the phase can reduce the content of Al in the alpha phase to a certain extent, thereby enhancing the corrosion resistance of the alpha phase; when the Mn content exceeds 15%, a residue may be generated during the casting process, and thus, the Mn content is controlled to 10.1 to 15% in the present invention. According to the invention, the microstructure of the alloy is refined by adding the manganese element with higher content, and the generation of alpha phase and k phase is promoted, so that the corrosion resistance, the wear resistance and the strength of the alloy are improved.

The microstructure of the aluminum bronze alloy of the invention mainly comprises alpha phase, beta phase and gamma phase₂Phase and k phase composition; in the microstructure of the aluminum bronze alloy section, the area ratio of the alpha phase is 75-85%, and the number of the k phase is more than or equal to 1 multiplied by 10⁴Per mm². In the alloy of the present invention, the α phase is a copper-based substitutional solid solution, the crystal structure is an fcc structure, and is a matrix phase of the material, and the β phase (Cu)₃Al) and gamma₂Phase (Al)₄Cu₉) Is Al-rich phase and has the function of improving the yield strength and the hardness of the alloy, but if the beta + gamma-beta in the alloy₂Excessive phase content, gamma₂The phases are distributed in a net shape around the alpha phase, which causes brittle fracture of the alloy and is not beneficial to improving the fatigue resistance of the alloy. The inventor finds out in the experimental process that the corrosion of the aluminum bronze mainly occurs in beta and gamma₂In the two-phase mixed area, the corrosion of the alpha phase is less, and the alpha phase plays a role in protecting the k phase from the anode in the initial corrosion period in the corrosion process. When aluminum bronze is corroded, beta and gamma are generated in the same corrosion time₂The two-phase mixed region is corroded first. Therefore, in order to ensure sufficient corrosion resistance of the alloy, the proportion of the alpha phase should be ensured, so the invention controls the area ratio of the alpha phase in the microstructure on the section of the aluminum bronze alloy to be within the range of75-85%. Further, the k phase includes AlFe and AlFe₃、Ni₂MnAl and Al₅Ni₃Mn₂The intermetallic compound has an average grain size of less than or equal to 1.0 μm, and has a large enhancing effect on alloy strength, hardness, wear resistance and the like. Al-rich Al when Mn content is less than 10%₅Ni₃Mn₂Phase and Al₅Ni₃Mn₂The amount of the k phase is less, which is not beneficial to improving the corrosion resistance and the strength of the alloy. The inventor promotes Al-rich Al by adding 10.1-15% of high-content Mn₅Ni₃Mn₂Phase, Al-rich Al₅Ni₃Mn₂A large amount of k phase is generated, the hardness, the strength and the wear resistance of the alloy are effectively improved, and Al-rich Al is newly precipitated in the k phase₅Ni₃Mn₂And the Al content in the alpha phase is relatively reduced, and the corrosion resistance of the alpha phase is further improved.

k phase number is more than or equal to 1 multiplied by 10⁴Per mm²Compared with the aluminum bronze alloy with the Mn content of less than 10%, the number of the k phases in the alloy is increased by 1.5-2.5 times, and fine and dispersed k plays a role in dispersion strengthening relative to a matrix, so that the hardness, strength and wear resistance of the alloy are further improved.

In the weight percentage composition of the aluminum bronze alloy, the contents of Mn, Al and Fe are limited to meet the following requirements: Mn/(Al + Fe) is more than or equal to 0.9 and less than or equal to 1.6. The inventor of the invention has found through a large number of experiments that when the content relation of Mn, Al and Fe satisfies that Mn/(Al + Fe) is more than or equal to 0.9 and less than or equal to 1.6, Mn, Al and Fe can fully act to promote the generation of alpha phase and k phase, and at the same time, Fe and Mn are relative to gamma phase under the proportion₂The generation of phase can effectively inhibit the generation of gamma-iron, so that the strength and the hardness of the alloy are improved, and the excessive generation of gamma-iron is prevented₂The phase causes alloy brittle fracture, avoids the reduction of the fatigue property of the alloy, and has promotion effect on the grain refinement in the proportion control range. However, if the ratio of Mn/(Al + Fe) is less than 0.9, Al, Fe and Mn cannot sufficiently promote the formation of the alpha phase and the k phase, and excessive gamma is likely to precipitate₂The corrosion resistance of the alloy is reduced, the strength, the hardness and other properties are not improved sufficiently, and the alloy is resistant to corrosionDeterioration of fatigue performance; when the content of Mn/(Al + Fe) is more than 1.6, the mechanical property of the alloy is obviously reduced, the corrosion potential of the alloy is also reduced, and the corrosion resistance is deteriorated, so that the content relation of Mn, Al and Fe is limited to be more than or equal to 0.9 and less than or equal to 1.6.

Preferably, the high manganese aluminum bronze alloy of the present invention further contains 0.001 to 2% in total of at least one element selected from the group consisting of Cr, Ti, Zr, Si, Co, P, B, Mg, Ag and RE. The Cr, Ti, Co, Ag and RE are added to facilitate the improvement of the strength and the hardness of the alloy, one part of the elements can be dissolved in a matrix to play a role in solid solution strengthening, and the other part can be precipitated to form a fine dispersed phase in the heat treatment process to play a role in precipitation dispersion strengthening, but the mechanical property and the technological property of the alloy can be reduced to different degrees when the Cr, Ti, Co, Ag and RE are added too much. The addition of Si, P, B, Mg and Zr is beneficial to grain refinement, and the addition of the elements can form a large amount of fine and dispersed crystal nucleation in the process of solution solidification to play a role in grain refinement; however, if the amount of the compound is too much, a large amount of compounds or particles are formed in the alloy, and the compounds or particles are similar to the inclusion defects in the alloy, so that the conductivity of the alloy is influenced, and the improvement of the comprehensive performance of the alloy is not facilitated.

The preparation method of the corrosion-resistant high-manganese aluminum bronze alloy comprises the following steps of:

(1) taking the raw materials according to the proportion;

(2) putting the prepared raw materials into a smelting furnace, smelting at 1250-1350 ℃, and performing semi-continuous casting at 1150-1270 ℃ after melting to obtain an ingot;

(3) carrying out hot extrusion on the obtained cast ingot to obtain an extrusion blank, wherein the extrusion temperature is 700-800 ℃, and the extrusion ratio is 150-350;

(4) stretching and annealing the obtained extrusion blank on line;

(5) and (5) repeating the step (4) for a plurality of times until the required diameter of the finished product is achieved.

Preferably, in the step (4), the single-pass drawing processing rate is less than 30%; the temperature of on-line annealing is 500-850 ℃, and cooling is carried outThe way is water cooling. Under the annealing process, the increase of crystal grains in the alloy can be prevented, fine crystal grains are obtained after stretching, and the water cooling mode is favorable for Al-rich Al₅Ni₃Mn₂And (4) separating out a phase.

Compared with the prior art, the invention has the beneficial effects that: the main characteristics of the corrosion-resistant high-manganese aluminum bronze are that the addition amount of Mn element is increased, the addition proportion of Mn, Al and Fe elements is controlled, the grain structure is refined, and the generation of alpha phase and k phase is promoted, so that the strength, the wear resistance and the corrosion resistance of the alloy are effectively improved. The corrosion-resistant high-manganese aluminum bronze alloy can achieve the tensile strength of more than or equal to 900MPa, the yield strength of more than or equal to 700MPa, the elongation of more than or equal to 2 percent, the hardness of HV5 of more than or equal to 240, no corrosion in an acid atmosphere environment with the pH value of 3 for 120 hours, excellent corrosion resistance and good comprehensive performance. The aluminum bronze alloy can be used as a surfacing material for the inner wall of the hydraulic cylinder, and the excellent corrosion resistance of the aluminum bronze alloy can effectively prolong the service life of the hydraulic cylinder.

Drawings

FIG. 1 is a cross-sectional microstructure of the corrosion-resistant high manganese aluminum bronze alloy of example 2 under a scanning electron microscope.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

According to the components of 10 example alloys and 4 comparative example alloys in the table 1, the raw materials are respectively taken and mixed according to the proportion, then the raw materials are smelted at 1250-1350 ℃, the smelted raw materials are semi-continuously cast at 1150-1270 ℃ to form ingots, then hot extrusion is carried out, the extrusion temperature is 700-800 ℃, the extrusion ratio is 150-350, then the product is subjected to stretching treatment by less than 30% of processing amount, and on-line annealing is carried out at 500-850 ℃, the cooling mode is water cooling, and the stretching and on-line annealing are repeated for multiple times until wire rod samples with the size of phi 1.2mm are obtained.

For the wire rod samples of 10 example alloys and 4 comparative example alloys prepared, tensile strength, yield strength, elongation, hardness, area ratio of alpha phase, number of k phase, corrosion resistance were measured, respectively.

Tensile test at room temperature according to GB/T228.1-2010 part 1 of tensile test for metallic materials: room temperature test method was carried out on an electronic universal tester using a round scale specimen (d 0: 8mm, specimen No. R5) at a tensile rate of 2 mm/min.

The grain size test is carried out on a metallographic microscope by using a point intercept method according to GB/T6394-.

The hardness test is carried out according to GB/T4340.1-2009 part 1 of Vickers hardness test of metal materials: test method "to determine HV 5.

Corrosion resistance test according to GB/T10125-2016 salt fog test for Artificial atmosphere Corrosion test CASS test, in pH 3 acetic acid atmosphere for 120h test.

The compositions and performance test results of the alloys of each example and comparative example are shown in tables 1 and 2, respectively. As can be seen from the table 1, the corrosion-resistant high-manganese aluminum bronze alloy can achieve the tensile strength of more than or equal to 900MPa, the yield strength of more than or equal to 700MPa, the elongation of more than or equal to 2 percent, the hardness of HV5 of more than or equal to 240, no corrosion occurs for 120h in an acid atmosphere environment with the pH value of 3, and the comprehensive performance is good.

As can be seen from comparative examples 1 to 4, the aluminum bronze alloy having an Mn content of less than 10% is inferior to the aluminum bronze alloy having a high manganese content of the present invention in terms of corrosion resistance and the like.

The cross-sectional microstructure of the corrosion-resistant high manganese aluminum bronze alloy of example 2 under a scanning electron microscope is shown in FIG. 1. As can be seen from FIG. 1, the fine k-phase is dispersed in the matrix, and the average grain size of the k-phase is less than or equal to 1.0 μm, and gamma₂The phases exist in the form of a bar.