CN116254436B - A high-strength and high-plasticity tin bronze alloy and its preparation method - Google Patents

Abstract

The invention discloses a high-strength high-plasticity tin bronze alloy and a preparation method thereof, and belongs to the technical field of copper alloy. The preparation method of the high-strength high-plasticity tin bronze alloy comprises the following steps: (1) Smelting tin bronze alloy, and then purifying and cooling to obtain molten metal; (2) Performing instantaneous supercooling induction nucleation on the metal liquid to obtain semi-solid slurry; (3) Homogenizing the semi-solid slurry to obtain homogenized semi-solid slurry; (4) Homogenizing semi-solid slurry, and performing extrusion molding to obtain tin bronze alloy; in the step (4), the temperature of the extrusion molding die is above 490 ℃. The invention avoids brittle phase delta-Cu by the synergistic effect of instantaneous supercooling induction nucleation of tin bronze alloy metal liquid and temperature regulation of a tin bronze alloy semi-solid slurry extrusion forming die ₄₁ Sn ₁₁ Generating, obtaining low tin primary alpha-Cu phase and high tin soft ductile phase alpha' -Cu _13.7 Sn phase and Cu phase ₃ And the tin bronze alloy formed by the P phase realizes the cooperative promotion of alloy strength and plasticity.

Description

A high-strength and high-plasticity tin bronze alloy and its preparation method

Technical field

The invention belongs to the technical field of copper alloys, and specifically relates to a high-strength and high-plasticity tin bronze alloy and a preparation method thereof.

Background technique

Due to its high strength, high stiffness, low friction coefficient, excellent seawater corrosion resistance, thermal conductivity and electrical conductivity, copper-tin alloy is used in friction devices such as bushings, bearing seats, gears, worm gears, as well as electrical connectors, multi-wire ultrasonic There are many applications in functional devices such as wire covering substrates and ultra-low temperature shape memory alloys. They have also become the preferred material for high-speed rail contact wires after copper-silver alloys. Its applications involve high-speed rail, ships, aviation and other major national economy and national defense construction fields.

As a typical solidification segregation alloy, copper-tin alloy easily forms a brittle and hard δ-Cu ₄₁ Sn ₁₁ phase when the tin content is greater than 10wt.%, seriously affecting its plasticity. During the solidification process, low-melting-point tin elements are easily enriched in the intergranular liquid phase under the action of capillaries between dendrites, forming reverse segregation. In addition, as the melt temperature continues to decrease and primary dendrites grow, the diffusion channel of enriched tin elements to the front end of the liquid phase is blocked, and the tin elements in the liquid phase can only be further enriched as the primary phase grows. After reaching the peritectic point composition, it solidifies into a quasi-peritectic β-Cu ₁₇ Sn ₃ phase. During the cooling process, the β-like phase first decomposes into the γ phase, and then decomposes into the intergranular brittle δ-Cu ₄₁ Sn ₁₁ phase at 520°C, which is extremely prone to intergranular brittle fracture, thus greatly limiting the application fields of Cu-Sn alloys.

In order to improve the mechanical properties of high-tin copper alloys, especially the plasticity, research is currently mainly conducted on solution annealing. For example, after 3D printing CuSn ₁₅ and semi-solid CuSn10P1 alloys, the elongation can be increased to 20-25% through high-temperature solution annealing at 500-700°C for more than 2 hours. However, the increase in plasticity comes at the expense of the strength of the material, and the strength decrease is basically more than Above 100MPa. Moreover, the tensile strength and elongation of CuSn10P1 alloy cast by sand casting and metal casting are only 220MPa and 310MPa, 3% and 2% respectively. Therefore, the development of high-strength and high-plasticity copper-tin alloys is of great strategic significance.

Contents of the invention

In view of the above shortcomings of the prior art, the present invention provides a tin bronze alloy with high strength and high plasticity and a preparation method thereof.

In order to achieve the above objects, the technical solutions adopted by the present invention are:

A method for preparing high-strength and high-plasticity tin bronze alloy, including the following steps:

(1) Smelt tin bronze alloy, then purify and cool down to obtain molten metal.

(2) Instantaneously supercool the molten metal to induce nucleation to obtain a tin bronze alloy semi-solid slurry.

(3) The tin bronze alloy semi-solid slurry is homogenized to obtain a homogenized semi-solid slurry.

(4) The homogenized semi-solid slurry is placed in an extruder for extrusion molding to obtain a high-strength and high-plasticity tin bronze alloy.

In the step (4), the extrusion molding die temperature is above 490°C.

Due to the large difference in atomic radius between Sn and Cu, Sn has a strong solid solution strengthening effect in Cu. In tin bronze alloys, as the tin content increases, the strength of the alloy increases, but the strength of low-content tin alloys cannot reach this level. The invention requires high strength, and when the tin content is greater than 10wt.%, it is easy to form a brittle and hard δ-Cu ₄₁ Sn ₁₁ phase, which will increase the brittleness of the alloy, seriously affect its plasticity, and have a negative impact on the strength of the alloy. The present invention solves this problem through two aspects. First, the instantaneous supercooling-induced nucleation technology of molten metal is used to cause the molten metal to nucleate explosively under a sufficiently strong chilling effect to form a spherical or nearly spherical low-tin primary α-Cu phase coexisting with the remaining high-tin liquid phase. A special semi-solid slurry allows the tin element in the remaining liquid phase to fully diffuse to the remote liquid phase. Second, by controlling the temperature of the extrusion mold, it is ensured that the semi-solid slurry maintains a certain cooling rate while meeting the thermodynamic conditions for the diffusion of tin elements, inhibiting the formation of β phase, and thus avoiding the intergranular brittle δ-Cu ₄₁ Sn ₁₁ phase. A high-strength and high-plasticity tin bronze alloy is obtained, which is composed of a low-tin spherical primary phase α-Cu, a high-tin soft and tough α′-Cu _13.7 Sn phase below the peritectic point, and a Cu ₃ P phase.

As a preferred embodiment of the present invention, in step (4), the extrusion mold temperature is 490°C-600°C.

After extensive experimental exploration, it is found that the extrusion molding die temperature of the present invention is 490°C-600°C, so that a high-strength and high-plasticity tin bronze alloy can be obtained.

As a preferred embodiment of the present invention, in the step (2), the cooling rate of the molten metal is 300-500°C/s.

The present invention completely avoids the problem of element segregation in the existing semi-solid slurry preparation technology by controlling the cooling rate of the tin bronze alloy metal liquid through a semi-solid preparation device, thereby avoiding obtaining the brittle phase δ-Cu ₄₁ Sn ₁₁ and obtaining the tin bronze The strength and plasticity of the alloy are significantly improved.

As a preferred embodiment of the present invention, in the step (3), the temperature of the homogenization treatment is 900-1050°C and the time is 10-25s.

The present invention uses a crucible with a preheating temperature of 900-1050°C to collect the tin bronze alloy semi-solid slurry, and performs a 10-25s homogenization treatment on the tin bronze alloy semi-solid slurry, which can ensure the uniformity of the microstructure of the semi-solid slurry. , while inhibiting the diffusion of Sn element from the α phase to the intergranular phase, so that the obtained tin bronze alloy has the best strength and plasticity.

As a preferred embodiment of the present invention, in step (4), the process parameters of extrusion molding are: the molding specific pressure is 145-175MPa, the filling speed is 17-27.5mm/s, and the heat preservation time of the extrusion molding mold is 1-5min.

As a preferred embodiment of the present invention, in step (1), the tin bronze alloy is smelted at a temperature of 1250-1350°C.

As a preferred embodiment of the present invention, in the step (1), after the tin bronze alloy is smelted, the temperature is maintained for 1-5 minutes, and then purified.

The tin bronze alloy smelting and heat preservation according to the present invention are carried out in a medium frequency induction heating furnace.

As a preferred embodiment of the present invention, in the step (1), after the heat preservation is completed, the melt temperature is lowered to 1200-1250°C and then purified; the purification treatment includes degassing and slag removal.

As a preferred embodiment of the present invention, in step (1), the temperature is lowered to 1070-1100°C to obtain molten metal.

The present invention also claims protection for the high-strength and high-plasticity tin bronze alloy prepared by the preparation method of the high-strength and high-plasticity tin bronze alloy.

The high-strength and high-plasticity tin bronze alloy obtained by the present invention is composed of a low-tin primary α-Cu phase, a high-tin soft and tough α'-Cu _13.7 Sn phase and a Cu ₃ P phase. The content of the Cu ₃ P phase is high. Less than 1wt% of tin bronze alloy with high strength and plasticity. Therefore, the high-strength and high-plasticity tin bronze alloy obtained by the present invention has high strength and high plasticity, with a tensile strength as high as 417 MPa and an elongation higher than 19%.

Compared with the prior art, the beneficial effects of the present invention are:

(1) In view of the requirement that tin bronze alloys have high strength and high plasticity at the same time, the present invention is different from the existing solid-state phase change heat treatment, deformation heat treatment and other technologies to obtain the alloy's dual-phase structure. Instead, for the first time, the molten metal is instantly passed through the casting method. The synergistic effect of cold-induced nucleation technology and extrusion mold temperature control has prepared a high-strength and high-strength polymer composed of low-tin primary α-Cu phase, high-tin soft and tough α′-Cu _13.7 Sn phase and Cu ₃ P phase. Plastic tin bronze alloy completely avoids the generation of brittle hard phase δ-Cu ₄₁ Sn ₁₁ , achieving a balance between high strength and high plasticity of the alloy, making the resulting alloy tensile strength >417Mpa and elongation 100% >19%. The invention provides the necessary structure and performance basis for the tin bronze alloy to expand into the field of plastic forming parts.

(2) The high-strength and high-plasticity tin bronze alloy prepared by the present invention has the characteristics of simple composition, simple preparation process, good structural uniformity, excellent mechanical properties, stable quality, strong controllability, and is suitable for industrial production.

Description of the drawings

Figure 1 is a schematic diagram of the preparation method of the high-strength and high-plasticity tin bronze alloy of the present invention;

Figure 2 is a microstructure diagram of the high-strength and high-plasticity tin bronze alloy prepared in Example 1. The circled area in the figure is the Cu ₃ P phase;

Figure 3 is an XRD pattern of the high strength and high plasticity tin bronze alloy prepared in Example 2;

Figure 4 is a microstructure diagram of the high-strength and high-plasticity tin bronze alloy prepared in Example 2. The circled area in the figure is the Cu ₃ P phase;

Figure 5 is a microstructure diagram of the high-strength and high-plasticity tin bronze alloy prepared in Example 3. The circled area in the figure is the Cu ₃ P phase;

Figure 6 is a microstructure diagram of the high-strength and high-plasticity tin bronze alloy prepared in Comparative Example 1;

Figure 7 is a comparison diagram of the stress-strain curves of the high-strength and high-plasticity tin bronze alloy prepared in Examples 6-8 and Comparative Example 5. Figure 1 is the stress-strain curve of the high-strength and high-plasticity tin bronze alloy described in Comparative Example 5. 2 is the stress-strain curve of the high-strength and high-plasticity tin bronze alloy described in Embodiment 6, 3 is the stress-strain curve of the high-strength and high-plasticity tin bronze alloy described in Embodiment 7, and 4 is the high-strength and high-plasticity tin bronze alloy described in Embodiment 8. Stress-strain curves of bronze alloys.

Detailed ways

In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

Figure 1 is a schematic diagram of the preparation method of the high-strength and high-plasticity tin bronze alloy according to the present invention. As can be seen from the figure, the present invention obtains molten metal from the tin bronze alloy through smelting, impurity removal and purification, and then circulates the molten metal into cooling water. CuSn10P1 semi-solid slurry was obtained by instantaneous supercooling-induced nucleation treatment. The semi-solid slurry was homogenized and then squeeze cast to obtain a high-strength and high-plasticity tin bronze alloy.

Example 1

The embodiments of a high-strength and high-plasticity tin bronze alloy and its preparation method according to the present invention are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1275°C. After the melting is completed, the heat preservation time in the furnace is 4 minutes. When the melt temperature drops to 1200°C, degassing and slag removal are performed. Treatment, then air cooling to 1085°C to obtain molten metal;

(2) Adjust the inclination angle of the semi-solid slurry preparation device to 45°, ensure that the length of the cooling channel in contact with the molten metal is 300mm, and the upper and lower circulating cooling water flow rates are 30ml/s and 35ml/s respectively. The cooling rate of the metal liquid treated by cold-induced nucleation is 380°C/s, and a tin bronze alloy semi-solid slurry is obtained;

(3) Use a crucible with a preheated temperature of 990°C to collect the tin bronze alloy semi-solid slurry, homogenize the tin bronze alloy semi-solid slurry for 18 seconds, and then quickly pour it into a bottom injection extruder;

(4) Set the extrusion molding specific pressure of the extruder to 150MPa, the filling speed to 24mm/s, and the mold temperature to 510°C. After completing the extrusion molding, keep it in the forming mold for 2.5 minutes and then remove the parts and cool them in the air. to room temperature to obtain high strength and high plasticity tin bronze alloy.

It can be seen from Figure 2 that the uniformity of the alloy structure is good, and comparing Figure 2 and Figure 6, it can be seen that since the microstructure of the high-strength and high-plasticity tin bronze alloy does not have the brittle hard phase δ-Cu ₄₁ Sn ₁₁ , it is conducive to improving the Tensile strength and plasticity of alloys.

Example 2

The embodiments of a high-strength and high-plasticity tin bronze alloy and its preparation method according to the present invention are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1300°C. After the melting is completed, the heat preservation time is 3 minutes in the furnace. When the melt temperature drops to 1210°C, degassing and slag removal are performed. Treatment, then air cooling to 1085°C to obtain molten metal;

(2) Adjust the inclination angle of the semi-solid slurry preparation device to 45°, ensure that the length of the cooling channel in contact with the molten metal is 300mm, and the upper and lower circulating cooling water flow rates are 30ml/s and 35ml/s respectively. The cooling rate of the metal liquid treated by cold-induced nucleation is 380°C/s, and a tin bronze alloy semi-solid slurry is obtained;

(3) Use a crucible with a preheated temperature of 990°C to collect the tin bronze alloy semi-solid slurry, homogenize the tin bronze alloy semi-solid slurry for 19 seconds, and then quickly pour it into a bottom injection extruder;

(4) Set the extrusion molding specific pressure of the extruder to 155MPa, the filling speed to 22mm/s, and the mold temperature to 525°C. After completing the extrusion molding, keep it in the forming mold for 2.5 minutes and then remove the parts and cool them in the air. to room temperature to obtain high strength and high plasticity tin bronze alloy.

As shown in Figure 3, the high-strength and high-plasticity tin bronze alloy parts obtained by the preparation method described in this embodiment are composed of α-Cu and α′-Cu _13.7 Sn, and it can be seen from Figure 4 that the uniformity of the alloy structure is relatively good. good. Comparing Figure 4 and Figure 6, it can be seen that the structural uniformity of the high-strength and high-plasticity tin bronze alloy parts obtained by the preparation method described in this embodiment has been greatly improved, and the microstructure of the alloy does not have a brittle hard phase δ- Cu ₄₁ Sn ₁₁ is beneficial to improving the tensile strength and plasticity of the alloy.

Example 3

The embodiments of a high-strength and high-plasticity tin bronze alloy and its preparation method according to the present invention are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1325°C. After the melting is completed, the heat preservation time is 2 minutes in the furnace. When the melt temperature drops to 1210°C, degassing and slag removal are performed. Treatment, then air cooling to 1085°C to obtain molten metal;

(2) Adjust the inclination angle of the semi-solid slurry preparation device to 45°, ensure that the length of the cooling channel in contact with the molten metal is 300mm, and the upper and lower circulating cooling water flow rates are 30ml/s and 35ml/s respectively. The cooling rate of the metal liquid treated by cold-induced nucleation is 380°C/s, and a tin bronze alloy semi-solid slurry is obtained;

(3) Use a crucible with a preheated temperature of 990°C to collect the tin bronze alloy semi-solid slurry, homogenize the tin bronze alloy semi-solid slurry for 25 seconds, and then quickly pour it into a bottom injection extruder;

(4) Set the extrusion molding specific pressure of the extruder to 145MPa, the filling speed to 20mm/s, and the mold temperature to 545°C. After completing the extrusion molding, keep it in the forming mold for 3 minutes, take out the parts, and cool in the air to At room temperature, high strength and high plasticity tin bronze alloy is obtained.

Comparing Figure 5 and Figure 6, it can be seen that the structural uniformity of the high-strength and high-plasticity tin bronze alloy parts obtained by the preparation method described in this embodiment has been greatly improved, and there is no brittle hard phase in the microstructure of the tin bronze alloy. δ-Cu ₄₁ Sn ₁₁ is beneficial to improving the tensile strength and plasticity of the alloy.

Example 4

The embodiments of a high-strength and high-plasticity tin bronze alloy and its preparation method according to the present invention are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1250°C. After the melting is completed, it is kept in the furnace for 5 minutes. When the melt temperature drops to 1250°C, degassing and slag removal are performed. Treatment, then air cooling to 1070°C to obtain molten metal;

(2) Adjust the inclination angle of the semi-solid slurry preparation device to 45°, ensure that the length of the cooling channel in contact with the molten metal is 300mm, and the upper and lower circulating cooling water flow rates are 30ml/s and 35ml/s respectively. The cooling rate of the metal liquid treated by cold-induced nucleation is 300°C/s, and a tin bronze alloy semi-solid slurry is obtained;

(3) Use a crucible with a preheating temperature of 900°C to collect the tin bronze alloy semi-solid slurry, homogenize the tin bronze alloy semi-solid slurry for 20 seconds, and then quickly pour it into a bottom injection extruder;

(4) Set the extrusion molding specific pressure of the extruder to 175MPa, the filling speed to 17mm/s, and the mold temperature to 490°C. After completing the extrusion molding, keep it in the forming mold for 1 minute, take out the parts, and cool in the air to At room temperature, high strength and high plasticity tin bronze alloy is obtained.

Example 5

The embodiments of a high-strength and high-plasticity tin bronze alloy and its preparation method according to the present invention are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1350°C. After the melting is completed, the holding time in the furnace is 1 minute. When the melt temperature drops to 1200°C, degassing and scraping are performed. Slag treatment, then air cooling to 1100℃ to obtain molten metal;

(2) Adjust the inclination angle of the semi-solid slurry preparation device to 45°, ensure that the length of the cooling channel in contact with the molten metal is 300mm, and the upper and lower circulating cooling water flow rates are 30ml/s and 35ml/s respectively. The cooling rate of the metal liquid treated by cold-induced nucleation is 500°C/s and the supercooling degree is 15°C, to obtain a tin bronze alloy semi-solid slurry;

(3) Use a crucible with a preheated temperature of 1050°C to collect the tin bronze alloy semi-solid slurry, homogenize the tin bronze alloy semi-solid slurry for 10 seconds, and then quickly pour it into a bottom injection extruder;

(4) Set the extrusion molding specific pressure of the extruder to 145MPa, the filling speed to 27.5mm/s, and the mold temperature to 600°C. After completing the extrusion molding, keep it in the forming mold for 5 minutes and then remove the parts and cool them in the air. to room temperature to obtain high strength and high plasticity tin bronze alloy.

Example 6

The embodiments of a high-strength and high-plasticity tin bronze alloy and its preparation method according to the present invention are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1285°C. After the melting is completed, the holding time in the furnace is 3.5 minutes. When the melt temperature drops to 1210°C, degassing and Slagging treatment, and then air cooling to 1080°C to obtain molten metal;

(2) Adjust the inclination angle of the tin bronze alloy semi-solid slurry preparation device to 45°, ensure that the length of the cooling channel in contact with the molten metal is 300mm, and the upper and lower circulating cooling water flow rates are 30ml/s and 35ml/s respectively. The cooling rate of the metal liquid subjected to instant supercooling-induced nucleation treatment is 360°C/s, and a tin bronze alloy semi-solid slurry is obtained;

(3) Use a crucible with a preheated temperature of 990°C to collect the tin bronze alloy semi-solid slurry, homogenize the tin bronze alloy semi-solid slurry for 19 seconds, and then quickly pour it into a bottom injection extruder;

(4) Set the extrusion molding specific pressure of the extruder to 145MPa, the filling speed to 22mm/s, and the mold temperature to 505°C. After completing the extrusion molding, keep it in the forming mold for 2.5 minutes and then take out the parts and cool them in the air. to room temperature to obtain high strength and high plasticity tin bronze alloy.

Example 7

The only difference between the high-strength and high-plasticity tin bronze alloy and its preparation method described in this embodiment and that of Embodiment 6 is that in step (4), the mold temperature is 525°C.

Example 8

The only difference between the high-strength and high-plasticity tin bronze alloy and its preparation method described in this embodiment and that of Embodiment 6 is that in step (4), the mold temperature is 545°C.

Comparative example 1

The only difference between the tin bronze alloy and its preparation method in this comparative example and Example 1 is that in step (4), the mold temperature is 485°C.

Comparative example 2

The only difference between the tin bronze alloy and its preparation method described in this comparative example and Example 2 is that in step (4), the mold temperature is 485°C.

Comparative example 3

The only difference between the tin bronze alloy and its preparation method described in this comparative example and Example 3 is that in step (4), the mold temperature is 485°C.

Comparative example 4

The only difference between the high-strength and high-plasticity tin bronze alloy and its preparation method described in this comparative example and Example 6 is that in step (4), the mold temperature is 610°C.

Comparative example 5

The only difference between the tin bronze alloy and its preparation method in this comparative example and Example 6 is that in step (4), the mold temperature is 485°C.

Comparative example 6

The tin bronze alloy and its preparation method described in this comparative example are as follows:

(1) Weigh 5kg of CuSn10P1 rod raw material and place it in a medium frequency induction heating furnace for melting. The melting temperature is 1275°C and the melting time is 4 minutes. When the melt temperature drops to 1200°C, degassing and slag removal are performed, and then air cooling is performed. to 1085°C to obtain molten metal;

(2) Air-cool the molten metal to 990°C, then use a crucible with a preheated temperature of 990°C to collect the tin bronze alloy molten metal, homogenize the tin bronze alloy molten metal for 18 seconds, and then quickly pour it into the bottom injection extruder in the press;

Set the extrusion molding specific pressure of the extruder to 150MPa, the filling speed to 24mm/s, and the mold temperature to 510°C. After completing the extrusion molding, keep it in the forming mold for 2.5 minutes, take out the parts, and cool to room temperature in the air. Obtain tin bronze alloy parts.

Comparative example 7

The only difference between the tin bronze alloy and its preparation method described in this comparative example and Example 1 is that in step (2), the cooling rate of the molten metal is 280°C/s.

Comparative example 8

The only difference between the tin bronze alloy and its preparation method described in this comparative example and Example 1 is that in step (2), the cooling rate of the molten metal is 520°C/s.

Test example 1

This test example is to test the tensile strength and elongation of the tin bronze alloy samples prepared in Examples 1-8 and Comparative Examples 1-8. The test results are shown in Table 1.

Table 1 Performance test results of tin bronze alloys prepared in Examples 1-8 and Comparative Examples 1-8

According to Table 1 and Figure 7, it can be seen that the tensile strength and elongation of the high-strength and high-plasticity tin bronze alloy of the present invention are significantly improved. In addition, according to Examples 6-8 and Comparative Examples 4-5, the present invention regulates the die temperature during extrusion and finds that the mechanical properties and plasticity of the alloy appear first as the die temperature increases during extrusion. The trend of rising and then falling. Moreover, compared with the tin bronze alloy prepared at a mold temperature of 485°C, the tensile strength of the high-strength and high-plasticity tin bronze alloy of the present invention increases from 367.1MPa to 463.9MPa, and the elongation significantly increases from 14.3% to 45.8%. It can be seen that the present invention The strength and plasticity of the high-strength and high-plasticity tin bronze alloy are significantly improved. Compared with Comparative Example 6, the tensile strength and elongation of the tin bronze alloy prepared in Example 7 of the present invention are 1.27 times and 8.4 times respectively that of the alloy prepared under liquid forming conditions in Comparative Example 6, which is higher than other traditional casting conditions. 5.07 times and 19.79 times that of alloy parts.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that The technical solution of the present invention may be modified or equivalently substituted without departing from the essence and scope of the technical solution of the present invention.

Claims (10)

1. The preparation method of the high-strength high-plasticity tin bronze alloy is characterized by comprising the following steps of:

(1) Smelting tin bronze alloy, and then purifying and cooling to obtain molten metal;

(2) Performing instantaneous supercooling induction nucleation on the metal liquid to obtain tin bronze alloy semi-solid slurry;

(3) Homogenizing the tin bronze alloy semi-solid slurry to obtain homogenized semi-solid slurry;

(4) Placing the homogenized semi-solid slurry in an extruder for extrusion molding to obtain high-strength high-plasticity tin bronze alloy;

in the step (4), the temperature of the extrusion molding die is above 490 ℃.

2. The method for producing a high-strength and high-plasticity tin bronze alloy as claimed in claim 1, wherein in the step (4), the die temperature for extrusion molding is 490 to 600 ℃.

3. The method for producing a high-strength and high-plasticity tin bronze alloy according to claim 1, wherein in the step (2), the cooling rate of the molten metal instantaneous supercooling-induced nucleation is 300 to 500 ℃/s.

4. The method for producing a high-strength and high-plasticity tin bronze alloy according to claim 1, wherein in the step (3), the homogenization treatment is performed at a temperature of 900 to 1050 ℃ for a period of 10 to 25 seconds.

5. The method for preparing a high-strength and high-plasticity tin bronze alloy according to claim 1, wherein in the step (4), the process parameters of extrusion molding are as follows: the molding specific pressure is 145-175MPa, the filling speed is 17-27.5mm/s, and the heat preservation time of the extrusion molding die is 1-5min.

6. The method for producing a high-strength and high-plasticity tin bronze alloy as set forth in claim 1, wherein in said step (1), the temperature at which the tin bronze alloy is melted is 1250 to 1350 ℃.

7. The method for producing a high-strength and high-plasticity tin bronze alloy according to claim 1, wherein in the step (1), after the tin bronze alloy is melted, the temperature is kept for 1 to 5 minutes, and then the purification treatment is performed.

8. The method for producing a high-strength and high-plasticity tin bronze alloy according to claim 7, wherein in the step (1), after the heat preservation is completed, the temperature of the melt is lowered to 1200-1250 ℃ and then the melt is purified; the purification treatment comprises degassing treatment and deslagging treatment.

9. The method for producing a high-strength and high-plasticity tin bronze alloy according to claim 1, wherein in the step (1), the temperature is lowered to 1070-1100 ℃ to obtain a molten metal.

10. A high strength and high plasticity tin bronze alloy as set forth in any one of claims 1 to 9.