A method for preparing titanium diboride reinforced iron-based composite material

Abstract

The present invention relates to a method for preparing a titanium diboride-reinforced iron-based composite material, comprising the following steps: S1. Thoroughly mixing titanium diboride powder and stainless steel powder to obtain a mixed powder; S2. Filling the mixed powder into a mold and performing compression molding to obtain a compact; S3. Removing the compact from the mold and sintering it in a hydrogen-molybdenum-wire push-boat furnace to obtain a titanium diboride-reinforced iron-based composite material. Compared with existing technologies, the present invention has simpler steps, and the resulting titanium diboride-reinforced iron-based composite material has a smaller grain size and better mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of metal-based composite material preparation, and in particular to a method for preparing a titanium diboride-reinforced iron-based composite material. Background Art

[0002] Steel is the most important metal structural material, with mature preparation processes and a wide variety of products. It is the most widely used metal material. In the fields of building materials, metallurgy, mining, electricity, cement, and mechanical engineering, there are high requirements for the wear resistance of materials. In order to reduce the wear and consumption of steel materials, components such as ball mill liners, crusher liners, and rolling mill rollers are usually made of high-chromium cast iron. However, with the emergence of new high-efficiency and energy-saving mills such as stirred mills, tower mills, and sand mills, the wear of liners and ball mill media has also increased significantly. By introducing a high-hardness, high-modulus particle reinforcement phase into the iron matrix, good friction and wear properties can be obtained and wear can be reduced. Iron-based composite materials are hard ceramic materials such as metal borides, metal carbides, metal nitrides, and metal oxides added to the matrix to improve the friction and wear properties of the material.

[0003] Although iron-based composites exhibit excellent friction and wear resistance, differences in the physical and chemical properties of the matrix and reinforcements also present challenges. For example, differences in thermal expansion coefficients between the matrix and reinforcements can lead to thermal mismatch stresses at the bonding interface. During sintering, interfacial reactions between the matrix and reinforcements can also occur, forming brittle compounds. Furthermore, interfacial voids can exist due to incomplete wetting between the matrix and reinforcements. These factors can negatively impact the mechanical properties of iron-based composites.

[0004] Furthermore, traditional powder metallurgy processes are complex. For example, Chinese invention patent application number 201511017247.5 (publication number CN 105618712A), titled "An Oxide Ceramic Reinforced Steel-Based Composite Material and Its Preparation Method," discloses an oxide ceramic reinforced steel-based composite material and its preparation method. The composite material is produced by a process comprising the following steps: 1) mixing molybdenum powder or molybdenum alloy powder with water and a binder to form a slurry; 2) applying the resulting slurry to the surface of an oxide ceramic or ceramic blank, drying, and sintering at 1650-2000°C to obtain a sintered body; 3) placing the resulting sintered body in a mold, pouring molten steel or iron at a temperature of 1400-1600°C, and casting the resulting body. This application requires the addition of a binder to the mixed powder, making the process complex. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a method for preparing a titanium diboride reinforced iron-based composite material with good mechanical properties.

[0006] The second technical problem to be solved by the present invention is to provide a method for preparing a titanium diboride reinforced iron-based composite material with a simple process.

[0007] The technical solution adopted by the present invention to solve the first and second technical problems is: a method for preparing a titanium diboride reinforced iron-based composite material, characterized in that it comprises the following steps:

[0008] S1. Thoroughly mix titanium diboride powder and stainless steel powder to obtain a mixed powder;

[0009] S2, filling the mixed powder into a mold and performing molding to obtain a compact;

[0010] S3. The compact is taken out from the mold and placed in a hydrogen molybdenum wire push boat furnace for sintering to obtain a titanium diboride reinforced iron-based composite material.

[0011] Preferably, the D50 of the stainless steel powder is 25 μm and / or 10 μm, and the D50 of the titanium diboride powder is 8 μm.

[0012] Preferably, in the step S1, during the powder mixing process, the volume fraction of titanium diboride reinforcement is 0% to 15%. Preferably, the step S1 is: fully mixing titanium diboride powder and stainless steel powder in a ball mill.

[0013] Preferably, the molding in step S2 is: sealing the mold and placing it in a cold isostatic press for molding.

[0014] Preferably, the molding pressure of the cold isostatic press is set to 90-180 MPa, and the holding time is set to 20-40 min.

[0015] Preferably, in step S3, the temperature of the hydrogen molybdenum wire pushing boat furnace is set to 900-1300° C., and the holding time is 40-80 minutes.

[0016] Compared with the prior art, the advantages of the present invention are as follows: the present invention uses fine-grained titanium diboride powder and stainless steel powder as raw materials, and adopts the method of cold isostatic pressing and reducing atmosphere sintering to prepare titanium diboride reinforced iron-based composite materials. Titanium diboride is a boride ceramic with high hardness, large elastic modulus and high temperature resistance, which can form a good interface with the iron matrix. Compared with traditional mechanical molding, the cold isostatic pressing method has a long holding time and a high density of the prepared green body. By utilizing the plasticity of the metal powder and the high pressure brought by the cold isostatic press to jointly form, the influence of the introduction of carbon atoms on the performance of the steel is avoided, so that the obtained titanium diboride reinforced iron-based composite material has a smaller grain size and good mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1XRD patterns of stainless steel powders in all examples;

[0018] Figure 2 is the XRD pattern of titanium diboride powder in all examples;

[0019] Figure 3 is a metallographic diagram of the titanium diboride reinforced iron-based composite material in Example 1;

[0020] Figure 4 is a metallographic image of the titanium diboride reinforced iron-based composite material in Example 4;

[0021] Figure 5 The XRD patterns of the blank before sintering and the titanium diboride reinforced iron-based composite material after sintering in Example 1;

[0022] Figure 6 Compression curves of titanium diboride reinforced iron-based composite materials in Example 1 and Example 4. DETAILED DESCRIPTION

[0023] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention are further described below with specific embodiments. However, the described embodiments are only part of the embodiments of the present invention and the protection scope of the present invention is not limited thereto.

[0025] Example 1: The volume fraction of titanium diboride in the composite material is 3%.

[0026] This embodiment includes the following steps:

[0027] Step 1. Weigh 491.39 g of stainless steel powder with a D50 of 25 μm, 491.39 g of stainless steel powder with a D50 of 10 μm, and 17.22 g of titanium diboride powder with a D50 of 8 μm. Thoroughly mix the weighed powders in a planetary ball mill to obtain a mixed powder. The milling speed was 300 rpm, the material-to-ball ratio was 3:1, and the milling time was 100 min.

[0028] Step 2: Fill the mixed powder into a mold, seal the mold, and place it in a cold isostatic press for molding. The working pressure of the cold isostatic press is 180 MPa, and the holding time is 30 minutes.

[0029] Step 3: Remove the compact from the mold and sinter it in a hydrogen-filled molybdenum wire push-boat furnace. The push-boat furnace's sintering temperature is set to 1150°C for 60 minutes. After cooling in the furnace, the sample is removed to obtain a titanium diboride-reinforced iron-based composite.

[0030] like Figure 3As shown, in Example 1, titanium diboride is evenly distributed in the composite material, and the grain size of the sample is about 20 μm. According to the national standard for grain size rating, the grain size is grade 8, which is fine grain. Figure 6 As shown, the sample in Example 1 has good plasticity, while the sample in Example 4 cracks when the strain reaches about 33%. This shows that the mechanical properties of the composite material can be controlled by adjusting the content of titanium diboride powder in the composite material.

[0031] Example 2: The volume fraction of titanium diboride in the composite material is 6%.

[0032] This embodiment includes the following steps:

[0033] Step 1. Weigh 482.55 g of stainless steel powder with a D50 of 25 μm, 482.55 g of stainless steel powder with a D50 of 10 μm, and 34.89 g of titanium diboride powder with a D50 of 10 μm. Thoroughly mix the weighed powders in a planetary ball mill to obtain a mixed powder. The milling speed was 300 rpm, the material-to-ball ratio was 3:1, and the milling time was 100 min.

[0034] Step 2: Fill the mixed powder into a mold, seal the mold, and place it in a cold isostatic press for molding. The working pressure of the cold isostatic press is 180 MPa, and the holding time is 30 minutes.

[0035] Step 3: Remove the compact from the mold and sinter it in a hydrogen-filled molybdenum wire push-boat furnace. The push-boat furnace's sintering temperature is set to 1150°C for 60 minutes. After cooling in the furnace, the sample is removed to obtain a titanium diboride-reinforced iron-based composite.

[0036] Example 3: The volume fraction of titanium diboride in the composite material is 9%.

[0037] This embodiment includes the following steps:

[0038] Step 1. Weigh 473.48 g of stainless steel powder with a D50 of 25 μm, 473.48 g of stainless steel powder with a D50 of 10 μm, and 53.05 g of titanium diboride powder with a D50 of 10 μm. Thoroughly mix the weighed powders in a planetary ball mill to obtain a mixed powder. The milling speed was 300 rpm, the material-to-ball ratio was 3:1, and the milling time was 100 min.

[0039] Step 2: Fill the mixed powder into a mold, seal the mold, and place it in a cold isostatic press for molding. The working pressure of the cold isostatic press is 180 MPa, and the holding time is 30 minutes.

[0040] Step 3: Remove the compact from the mold and sinter it in a hydrogen-filled molybdenum wire push-boat furnace. The push-boat furnace's sintering temperature is set to 1150°C for 60 minutes. After cooling in the furnace, the sample is removed to obtain a titanium diboride-reinforced iron-based composite.

[0041] Example 4: The volume fraction of titanium diboride in the composite material is 12%.

[0042] This embodiment includes the following steps:

[0043] Step 1. Weigh 464.15 g of stainless steel powder with a D50 of 25 μm, 464.15 g of stainless steel powder with a D50 of 10 μm, and 71.70 g of titanium diboride powder with a D50 of 10 μm. Thoroughly mix the weighed powders in a planetary ball mill to obtain a mixed powder. The milling speed was 300 rpm, the material-to-ball ratio was 3:1, and the milling time was 100 min.

[0044] Step 2: Fill the mixed powder into a mold, seal the mold, and place it in a cold isostatic press for molding. The working pressure of the cold isostatic press is 180 MPa, and the holding time is 30 minutes.

[0045] Step 3: Remove the compact from the mold and sinter it in a hydrogen-filled molybdenum wire push-boat furnace. The push-boat furnace's sintering temperature is set to 1150°C for 60 minutes. After cooling in the furnace, the sample is removed to obtain a titanium diboride-reinforced iron-based composite.

Claims

1. A method for preparing a titanium diboride reinforced iron-based composite material, characterized in that: The following steps are involved: S1. Thoroughly mix titanium diboride powder and 316L stainless steel powder to obtain a mixed powder; the D50 of the stainless steel powder is 25 μm and 10 μm, and the D50 of the titanium diboride powder is 8 μm; during the powder mixing process, the volume fraction of the titanium diboride powder is 3% to 15%; S2. Filling the mixed powder into a mold, sealing the mold and placing it in a cold isostatic press for molding to obtain a compact; the molding pressure of the cold isostatic press is set to 90-180 MPa, and the holding time is set to 20-40 min; S3, taking out the compact from the mold and placing it in a hydrogen molybdenum wire push boat furnace for sintering to obtain a titanium diboride reinforced iron-based composite material; The temperature of the hydrogen molybdenum wire pushing boat furnace is set to 900-1300° C., and the holding time is 40-80 minutes.

2. The method for preparing a titanium diboride reinforced iron-based composite material according to claim 1, characterized in that: The step S1 is: fully mixing titanium diboride powder and stainless steel powder in a ball mill.

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