MN-CU-Based Damping Alloy Powder For Use In Selective Laser Melting Process And Preparation Method Thereof

Abstract

The present invention belongs to the technical field of metal materials for additive manufacturing, and relates to a Mn—Cu-based damping alloy powder for use in a selective laser melting (SLM) process and a preparation method thereof. The powder has chemical components in percent by weight as follows: C: ≤0.15%, Ni: 4.9-5.2%, Si: ≤0.15%, Fe: 1.8-5.0%, Cu: 20-23%, P: ≤0.03%, S: ≤0.06%, and the balance being Mn and inevitable impurities. The preparation method includes: preparation of master alloy, powdering by vacuum induction melting gas atomization (VIGA), mechanical vibrating and air classification screening under protection of an inert gas and collecting. Compared with the prior art, the powder of the present invention has a high sphericity, a high apparent density, a small angle of repose, a desired fluidity and a relatively high yield of fine powders having a size of 15-53 μm.

Claims

1. A Mn—Cu-based damping alloy powder for use in a selective laser melting (SLM) process, comprising chemical components in percent by weight as follows: C: ≤0.15%, Ni: 4.9-5.2%, Si: ≤0.15%, Fe: 1.8-5.0%, Cu: 20-23%, P: ≤0.03%, S: ≤0.06%, and the balance being Mn and inevitable impurities.

2. A 3D printed manufactured part comprising: an alloy comprising chemical components in percent by weight as follows: C: ≤0.15%, Ni: 4.9-5.2%, Si: ≤0.15%, Fe: 1.8-5.0%, Cu: 20-23%, P: ≤0.03%, S: ≤0.06%, and the balance being Mn and inevitable impurities, wherein based on the above components in percent by weight, the 3D printed manufactured part obtained after selective laser melting (SLM) additive manufacturing and heat treatment has a tensile strength >560 MPa at room temperature, a yield strength >300 MPa, an elongation rate of more than 20% and a damping performance Q.sup.−1 of above 0.028 at room temperature.

3. A method of preparing the Mn—Cu-based damping alloy powder for use in an SLM process according to claim 1, comprising the steps of: preparing a master alloy with vacuum induction melting (VIM), wherein components of the master alloy are as follows: C: ≤0.15%, Ni: 4.9-5.2%, Si: ≤0.15%, Fe: 1.8-5.0%, Cu: 20-23%, P: ≤0.03%, S: ≤0.06%, and the balance being Mn and inevitable impurities; putting the master alloy into a melting pot, vacuumizing a melting chamber to a pressure below 0.1 Pa, filling with argon with a purity of 99.999% or more until the pressure in the melting chamber returns to a standard atmospheric pressure, induction heating the master alloy to 1,300-1,500° C. for complete melting, pouring a molten metal liquid into a MgO tundish, performing supersonic atomization with argon having a purity of 99.999% as a medium at a pressure of 6.0-8.0 MPa to obtain powders, cooling atomized metal powders in a cooling chamber and directly collecting the metal powders in a sealed container under a cyclone separator; subjecting the metal powders in a powder collecting tank to mechanical vibration and air classification screening under protection of an inert gas, vacuum sealing and packing screened metal powders having a particle size of 15-53 μm for use in an SLM technology; putting said Mn—Cu-based damping alloy powders having a particle size of 15-53 μm into SLM laser additive manufacturing equipment, preparing standard parts with mechanical properties wherein laser printing is carried out with a spot diameter of 70-100 μm, a laser power of 200-280 W, a scanning speed of 900-1,100 mm/s, a pass distance of 100-150 μm and a single layer spreading thickness of 20-30 μm, and the printing allows a part to have a density of more than 99.5%; subjecting additive manufactured standard parts to heat isostatic pressing+solution treatment+aging treatments, wherein the heat isostatic pressing is carried out at 800-950° C. for 2-4 h at ≥100 MPa; the solution treatment is carried out at 880-920° C. for 2-4 h with subsequent water cooling to room temperature; the aging is carried out at 400-450° C. for 3-6 h with subsequent air cooling to room temperature.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 shows particle size distribution of the metal powders in Example 1.

[0025] FIG. 2 shows the macromorphology of the metal powders in Example 2.

[0026] FIG. 3 shows the morphology of internal structure of the metal powder in Example 3.

[0027] FIG. 4 shows the relationship between temperature and damping performance of the printed piece of Example 1 after HIP850 and HIP920 heat treatments.

[0028] FIG. 5 shows the metallographic structure of the printed part of Example 2 after heat treatment (HIP850).

[0029] FIG. 6 shows the metallographic structure of the printed part of Example 2 after heat treatment (HIP920).

[0030] FIG. 7 shows a graph of the morphology of the transmission (transmission electron microscope (TEM)) structure of the printed part of Example 3 after treatment with the HIP850 system.

[0031] FIG. 8 shows another graph of the morphology of the transmission (TEM) structure of the printed part of Example 3 after treatment with the HIP850 system.

DETAILED DESCRIPTION

Example 1

[0032] Step (1): preparation of master alloy: a master alloy was prepared with a VIM furnace, where components of the master alloy were as follows: C: 0.05%, Ni: 5.19%, Si: 0.05%, P: 0.008%, S: 0.016%, Fe: 4.13%, Cu: 20.4%, and the balance being Mn and inevitable impurities.

[0033] Step (2): powdering by VIGA: the master alloy was put into a melting pot. A melting chamber was vacuumized to a pressure below 0.1 Pa, and filled with argon with a purity of 99.999% or more until the pressure in the melting chamber returned to a standard atmospheric pressure. The master alloy was induction heated to 1,400° C. for complete melting. Then a molten metal liquid was poured into a MgO tundish. Supersonic atomization was performed with argon having a purity of 99.999% as a medium at a pressure of 6.5 MPa to obtain powders. Atomized metal powders were cooled in a cooling chamber and directly collected in a sealed container under a cyclone separator. The metal powders in a powder collecting tank were subjected to mechanical vibration and air classification screening under protection of an inert gas. Metal powders having a particle size of 15-53 μm for use in an SLM technology were sealed by vaccumization and packed.

[0034] Step (3): SLM-based preparation of standard parts: invented Mn—Cu-based damping alloy powders having a particle size of 15-53 μm were put into SLM laser additive manufacturing equipment. Standard parts with mechanical properties were prepared where laser printing was carried out with a spot diameter of 80 μm, a laser power of 250 W, a scanning speed of 1,000 mm/s, a pass distance of 150 μm and a single layer spreading thickness of 30 μm.

Example 2

[0035] Step (1): preparation of master alloy: a master alloy was prepared with a VIM furnace, where components of the master alloy were as follows: C: 0.028%, Ni: 4.93%, Si: 0.03%, P: 0.007%, S: 0.058%, Fe: 2.18%, Cu: 22.5%, and the balance being Mn and inevitable impurities.

[0036] Step (2): powdering by VIGA: the master alloy was put into a melting pot. A melting chamber was vacuumized to a pressure below 0.1 Pa, and filled with argon with a purity of 99.999% or more until the pressure in the melting chamber returned to a standard atmospheric pressure. The master alloy was induction heated to 1,450° C. for complete melting. Then a molten metal liquid was poured into a MgO tundish. Supersonic atomization was performed with argon having a purity of 99.999% as a medium at a pressure of 7.0 MPa to obtain powders. Atomized metal powders were cooled in a cooling chamber and directly collected in a sealed container under a cyclone separator. The metal powders in a powder collecting tank were subjected to mechanical vibration and air classification screening under protection of an inert gas. Metal powders having a particle size of 15-53 μm for use in an SLM technology were sealed by vaccumization and packed.

[0037] Step (3): SLM-based preparation of standard parts: invented Mn—Cu-based damping alloy powders having a particle size of 15-53 μm were put into SLM laser additive manufacturing equipment. Standard parts with mechanical properties were prepared where laser printing was carried out with a spot diameter of 80 μm, a laser power of 230 W, a scanning speed of 950 mm/s, a pass distance of 120 μm and a single layer spreading thickness of 30 μm.

Example 3

[0038] Step (1): preparation of master alloy: a master alloy was prepared with a VIM furnace, where components of the master alloy were as follows: C: 0.11%, Ni: 5.14%, Si: 0.06%, P: 0.018%, S: 0.037%, Fe: 4.86%, Cu: 22.4%, and the balance being Mn and inevitable impurities.

[0039] Step (2): powdering by VIGA: the master alloy was put into a melting pot. A melting chamber was vacuumized to a pressure below 0.1 Pa, and filled with argon with a purity of 99.999% or more until the pressure in the melting chamber returned to a standard atmospheric pressure. The master alloy was induction heated to 1,480° C. for complete melting. Then a molten metal liquid was poured into a MgO tundish. Supersonic atomization was performed with argon having a purity of 99.999% as a medium at a pressure of 7.5 MPa to obtain powders. Atomized metal powders were cooled in a cooling chamber and directly collected in a sealed container under a cyclone separator. The metal powders in a powder collecting tank were subjected to mechanical vibration and air classification screening under protection of an inert gas. Metal powders having a particle size of 15-53 μm for use in an SLM technology were sealed by vaccumization and packed.

[0040] Step (3): SLM-based preparation of standard parts: invented Mn—Cu-based damping alloy powders having a particle size of 15-53 μm were put into SLM laser additive manufacturing equipment. Standard parts with mechanical properties were prepared where laser printing was carried out with a spot diameter of 80 μm, a laser power of 260 W, a scanning speed of 1,100 mm/s, a pass distance of 150 μm and a single layer spreading thickness of 25 μm.

[0041] Table 1 and Table 2 respectively showed the alloy components, particle size distribution intervals and yields of fine powders having a particle size of 15-53 μm of the metal powders in Examples 1-3. It can be seen that, the Mn—Cu-based powders prepared by the VIGA method of the present invention had a relatively large content of fine powders with a high yield of fine powders in a corresponding range of 15-53 μm, which was very suitable for industrial production and promotion of application. Table 3 showed the physical property test results of the metal powders of Examples 1-3. It can be seen that the Mn—Cu-based damping alloy powders of the present invention had a high apparent density (>3.8 g/cm.sup.3), a small angle of repose (<34°) and a desired fluidity index (>85%), showing extremely excellent comprehensive performances. These properties were critical to excellent comprehensive mechanical properties and damping performance of later 3D printed standard parts.

[0042] Table 4 showed the test results of the mechanical properties and the damping performance of the metal powders prepared in Examples 1-3 after SLM printing and corresponding heat treatments. All the examples were implemented with two post-processing treatments, namely an HIP850 system: 850° C./3 h (pressure of 120 MPa) with cooling in a furnace+880° C./2 h with water cooling+425° C./4 h with air cooling; and an HIP920 system: 920° C./3 h (pressure of 120 MPa) with cooling in a furnace+900° C./2 h with water cooling+425° C./4 h with air cooling. It can be seen that, after the two heat treatment systems, the examples had extremely excellent mechanical properties matching the damping performance with the tensile strength >560 MPa at room temperature, the yield strength >300 MPa, the elongation rate of more than 20% and the damping performance Q.sup.−1 of above 0.028 at room temperature.

[0043] FIG. 1 showed particle size distribution of the metal powders in Example 1. The macromorphology of the metal powders in Example 2 was characterized with an TEM and shown in FIG. 2. It can be seen that, the Mn—Cu-based damping alloy powders developed by the present invention had high surface smoothness and desired sphericity. FIG. 3 showed the morphology of the internal structure of the metal powder in Example 3. It can be seen that, the powder had internal solidification structures mainly in forms of a columnar crystal+an equiaxed crystal, and internal crossed phase interfaces. FIG. 4 showed the relationship between temperature and damping performance of the printed part of Example 1 after HIP850 and HIP920 heat treatments. It can be seen that, the powders developed by the present invention had excellent damping performance after printing and heat treatments. FIGS. 5 and 6 showed the metallographic structures of the printed part of Example 2 after HIP850 and HIP920 treatment respectively. It can be seen that, there was a large number of twin microstructures in the martensite matrix structure, and this was the most important reason why the present invention had excellent damping performance and mechanical properties. FIGS. 7-8 showed graphs of the morphology of the transmission (TEM) structure of the printed part of Example 3 after treatment with the HIP850 system.

[0044] The above merely describes some preferred examples of the present invention, and the protection scope of the present invention is not limited to the above specific embodiments. The above specific embodiments are illustrative and not restrictive. Where the materials and methods of the present invention are used, all specific extensions without departing from the purpose of the present invention and the protection scope of the claims should fall within the protection scope of the present invention.

TABLE-US-00001 TABLE 1 Alloy components of the metal powders in the examples (wt. %) Example C Si P S Ni Cu Fe Mn Example 1 0.021 0.042 <0.005 0.012 5.14 20.17 3.85 70 Example 2 0.014 0.018 <0.005 0.058 4.78 22.71 1.96 65.11 Example 3 0.074 0.043 0.016 0.03 5.1 22.62 4.46 66.1

TABLE-US-00002 TABLE 2 Particle size distribution and yield of fine powders having a particle size of 15-53 μm in the examples D10 D50 D90 15-53 pm fine powders Example (μm %) (μm) (μm) Yield (%) Example 1 17.7 28.82 46.45 29.2 Example 2 18.2 28.99 52.1  28.6 Example 3 13.3 29.65 48.01 31.4

TABLE-US-00003 TABLE 3 Test results of physical properties in the examples Apparent Tap Degree of density density Angle of Fluidity compression Example (g/cm.sup.3) (g/cm.sup.3) repose (°) index % Example 1 3.81 4.41 29.42 87.5 13.15 Example 2 3.88 4.53 33.06 85 14.35 Example 3 3.82 4.31 31.31 90 11.37

TABLE-US-00004 TABLE 4 Mechanical properties and damping performance of the metal powders in examples after heat treatments Tensile Yield Damping strength, strength, Elongation performance Q.sup.−1 MPa MPa rate, % at room temperature Example 1 HIP850 641 388 20.5 0.030 HIP920 602 318 30.5 0.029 Example 2 HIP850 625 375 21.5 0.031 HIP920 578 308 34.5 0.028 Example 3 HIP850 628 380 22.0 0.029 HIP920 580 311 31.5 0.029