Ni3Al / carbide composite material powder, laser cladding method thereof and application thereof

Abstract

The application relates to a Ni3Al / carbide composite material powder and a laser cladding method and application thereof, and belongs to the technical field of laser processing materials. The Ni3Al / carbide composite material powder comprises the following components in percentage by mass: Al: 9.5-10.0%, C: 1.1-1.6%, Cr: 18.0-19.5%, B: 0.05-0.07%, O<=200ppm, N<=50ppm, H<=10ppm, and the balance of Ni; the atomic number ratio of the nickel equivalent and the aluminum equivalent is 2.5-2.9; the Ni3Al / carbide composite material powder comprises a NiAl phase, the carbide structure is Cr7C3, and the mass content of the Cr7C3 is 13-18%. The application effectively improves the mechanical processing performance of a cladding layer; meanwhile, the hardness of the cladding layer is improved, the wear resistance is good, and the surface performance demand of key parts of a heavy-load diesel engine can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser processing materials, and in particular to a Ni3Al / carbide composite material powder and a laser cladding method and application thereof. BACKGROUND

[0002] In recent years, heavy-duty diesel engines are developing towards high mechanical load, high thermal load and low emission, and the internal working environment is becoming increasingly harsh. The harsh working environment puts extremely high requirements on the surface wear resistance, fatigue resistance, heat insulation, oxidation resistance and other properties of key components of heavy-duty diesel engines, and the existing material structure, coating material system and coating technology all have great limitations. Therefore, developing new coating material systems and their preparation technologies to improve the quality and performance of key components has become a key technical problem that needs to be solved by domestic and foreign diesel engine research and application units.

[0003] Ni3Al alloy and Ni3Al / carbide composite material are considered to be ideal high-temperature high-strength wear-resistant materials. Chinese patent 201410822105.5 provides a method for preparing a Ni3Al / Cr3C2 composite coating with compact organizational structure, high bonding strength with the substrate and good wear resistance by using laser cladding technology, which has good application prospects in the field of heavy-duty high-power diesel engines. However, this technology uses a mixture of Ni3Al alloy powder and Cr3C2 powder as cladding powder, which is prone to cracks and uneven distribution of carbides, seriously affecting the engineering application of the Ni3Al / Cr3C2 composite coating. In order to solve the above problems, Chinese patent application CN115011843A discloses a method for preparing an in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer using laser cladding process technology, which suppresses the formation of cladding cracks and promotes the uniform distribution of cladding carbides within a larger cladding process parameter range. However, due to the use of this technology, the proportion of cladding carbide Cr7C3 is relatively high (mass content of 22% to 28%), which leads to poor mechanical processing (cutting) performance of the Ni3Al / Cr7C3 cladding layer.

[0004] In order to improve the mechanical processing (cutting) performance of the in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer, reducing the proportion of carbides in the cladding layer is an effective method. However, while reducing the proportion of carbides, the Ni3Al-based alloy strengthening layer still needs to maintain high hardness and good wear resistance, which is a difficult problem. SUMMARY

[0005] In view of the above analysis, the present application aims to provide a Ni3Al / carbide composite material powder and a laser cladding method and application thereof, so as to solve at least one of the following problems of the prior art: improving the machinability of the Ni3Al / carbide composite material powder, and maintaining high hardness, good wear resistance and interfacial shear strength of the material.

[0006] The object of the present application is mainly achieved by the following technical solutions:

[0007] The present application provides a Ni3Al / carbide composite material powder, the chemical composition of which is, in mass percentage: Al: 9.5% to 10.0%, C: 1.1% to 1.6%, Cr: 18.0% to 19.5%, B: 0.05% to 0.07%, O≤200ppm, N≤50ppm, H≤10ppm, and the balance being Ni; in the Ni3Al / carbide composite material powder, the atomic ratio of nickel equivalent to aluminum equivalent is 2.5 to 2.9, the Ni3Al / carbide composite material powder comprises a NiAl phase, and the carbide structure of the Ni3Al / carbide composite material powder is Cr7C3, and the mass content of Cr7C3 is 13% to 18%.

[0008] Preferably, the particle size of the Ni3Al / carbide composite material powder ranges from 53μm to 124μm.

[0009] The present application also provides a laser cladding method of a Ni3Al / carbide composite material powder, comprising the following steps: step 1: using a coaxial powder feeding method to feed the Ni3Al / carbide composite material powder to the surface of a steel material; and step 2: using a laser cladding method to clad the Ni3Al / carbide composite material powder on the surface of the steel material to form an in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer.

[0010] Preferably, the coaxial powder feeding amount of the coaxial powder feeding method is 10g / min to 30g / min.

[0011] Preferably, the power of the laser cladding is 1400W to 2600W, and the scanning speed is 0.12m / min to 0.60m / min.

[0012] Preferably, the laser beam of the laser cladding method is a circular spot or a rectangular spot.

[0013] In addition, the application further provides an in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer, which is formed on the surface of a steel material by a laser cladding method, and comprises a Ni3Al phase, a NiAl phase and a carbide Cr7C3, wherein the carbide Cr7C3 is dispersedly distributed in the Ni3Al phase, the average hardness of the Ni3Al-based alloy strengthening layer is 620-680 HV, the wear rate is less than or equal to 0.8*10 -5 mm 3 / (N*m), and the shear strength of the bonding interface with the steel material is 400-600 MPa.

[0014] Preferably, the Ni3Al-based alloy strengthening layer is prepared by the laser cladding method.

[0015] Preferably, the steel material is one of carbon steel, alloy steel, heat-resistant stainless steel and cast iron.

[0016] In addition, the application further provides an application of a Ni3Al / carbide composite material powder, which is used for surface modification of a steel or nickel-based alloy part of a heavy-duty diesel engine.

[0017] Compared with the prior art, the application can at least achieve one of the following beneficial effects:

[0018] A) In the application, the content of the carbide Cr7C3 is about 13-18%, which can effectively improve the machining (cutting) performance of the cladding layer; meanwhile, the equivalent atomic ratio of nickel and aluminum is 2.5-2.9, which promotes the formation of a NiAl hard phase and improves the hardness of the cladding layer, so that the Ni3Al-based alloy strengthening layer can maintain a high hardness and good wear resistance while reducing the proportion of carbides in the cladding layer, and can meet the demand for surface performance of key parts of a heavy-duty diesel engine.

[0019] B) In the application, the laser cladding technology is used to prepare the in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer, the Cr7C3 is formed in-situ again after melting, the size of the Cr7C3 can be reduced, and the combination with the Ni3Al-based phase is better. The Ni3Al-based alloy strengthening layer is metallurgically combined with the substrate, and the interface shear strength can reach 400-600 MPa.

[0020] Other features and advantages of the application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the structure particularly pointed out in the written description and claims hereof. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application.

[0022] Figure 1 A morphology diagram of the Ni3Al / carbide composite material powder prepared by the vacuum induction melting-inert gas atomization method in Example 1 provided by the present application;

[0023] Figure 2 A morphology diagram of the in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer formed after laser cladding in Example 1 provided by the present application.

[0024] Figure 3 A morphology diagram of the microstructure in the in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer formed after laser cladding in Example 1 provided by the present application. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present application will be described in detail with reference to the drawings, which form a part of this application, and together with the description serve to explain the principles of the present application.

[0026] The present application provides a Ni3Al / carbide composite material powder, the chemical composition of which is, in mass percentage, Al: 9.5%-10.0%, C: 1.1%-1.6%, Cr: 18.0%-19.5%, B: 0.05%-0.07%, O≤200ppm, N≤50ppm, H≤10ppm, and the balance of Ni; in the Ni3Al / carbide composite material powder, the atomic number ratio of nickel equivalent and aluminum equivalent is 2.5-2.9, the Ni3Al / carbide composite material powder contains a NiAl phase with a mass content of about 2.5%-8.5%, and the carbide structure of the Ni3Al / carbide composite material powder is Cr7C3, the mass content of Cr7C3 being 13%-18%, which is dispersedly distributed in the Ni3Al base phase.

[0027] Specifically, in the present application, the calculation principle of the atomic number of nickel equivalent is:

[0028]

[0029] The calculation principle of the atomic number of aluminum equivalent is:

[0030]

[0031] wherein, Cr Ni3Al溶 is 4%-10%, Ni represents the mass percentage of the Ni element in the Ni3Al / carbide composite material powder, and Al represents the mass percentage of the Al element in the Ni3Al / carbide composite material powder.

[0032] Specifically, as preferred, the mass percentage of each component is: Al: 9.6% to 9.95%, C: 1.3% to 1.45%, Cr: 18.9% to 19.5%, B: 0.05% to 0.06%, O: 40 to 180 ppm, N: 26 to 37 ppm, H: 3 to 4 ppm, as preferred, the atomic ratio of nickel equivalent and aluminum equivalent is 2.75 to 2.85, and the mass content of Cr7C3 is 15% to 17%.

[0033] It should be noted that generally, the atomic ratio of nickel and aluminum equivalent of the Ni3Al phase is 3, and the present application reduces the atomic ratio of nickel and aluminum equivalent by reducing the content of nickel and increasing the content of aluminum, thereby promoting the formation of the NiAl phase, so that the Ni3Al phase and the NiAl phase coexist in the Ni3Al / carbide composite powder. The hardness of the Ni3Al phase is 300 to 400 HV, the hardness of the NiAl phase is 500 to 700 HV, and the hardness of the Cr7C3 type carbide is more than 1200 HV, so the increase of the NiAl phase helps to improve the hardness of the cladding layer after laser cladding, and provides a basis for maintaining good wear resistance.

[0034] It should be noted that when the atomic ratio of nickel equivalent and aluminum equivalent is less than 2.5, the proportion of the NiAl phase is large, the plasticity of the NiAl phase is poor, and cracks are easily formed.

[0035] In addition, the fine and dispersed Cr7C3 hard phase plays a supporting role, separates the friction surface, reduces the direct interaction between the friction pair, and can improve the wear resistance. The mass content of Cr7C3 in the composite powder provided by the present application is 13% to 18%, and compared with the Chinese patent application with publication number CN115011843A, the reduction of carbide content helps to improve the machining performance of the Ni3Al-based alloy strengthening layer. When the mass content of Cr7C3 is less than 13%, the high-hardness carbide strengthening phase is less, which is not enough to effectively separate the friction surface, resulting in a decrease in the wear resistance of the cladding layer.

[0036] It should be noted that Ni3Al alloy has room temperature brittleness, and a small amount of B can improve the room temperature ductility of Ni3Al and inhibit crack formation, but in the case of excessive B element, B is enriched on the grain boundary, promoting the formation of thermal cracks. Within the chemical composition range of the composite powder of the present application, when the B content is less than 0.05%, it cannot play a role in improving the plasticity of Ni3Al, and when the B content is higher than 0.07%, the cladding layer has a greater tendency to form thermal cracks. The B content of the present application is determined to be 0.05% to 0.07%, which not only ensures the room temperature ductility of the Ni3Al-based phase of the cladding layer, but also inhibits the formation of thermal cracks.

[0037] It should be noted that the impurity elements such as O, H and N will participate in the metallurgical reaction in the laser cladding process of the Ni3Al / carbide composite material powder. When the content of O is excessive, fatigue problem is prone to occur in the carbide reinforced Ni3Al-based alloy cladding layer, and the wear amount increases; when the content of N is excessive, AlN is prone to form, and the crack tendency increases; when the content of H is excessive, the brittleness of the cladding layer is increased. The content limitation of the impurity elements has extremely important engineering value, and determines the metallurgical process and economy of the powder material. The content of O, N and H elements in the powder is limited to ≤200ppm, ≤50ppm and ≤10ppm.

[0038] Specifically, the particle size of the Ni3Al / carbide composite material powder ranges from 53μm to 124μm, and preferably ranges from 75μm to 105μm.

[0039] It should be noted that if the particle size of the composite material powder is too large, unmelted powder will appear during laser cladding, and if the particle size is too small, the composite material powder is prone to be rubbed with the powder feeding equipment and block the equipment during the laser cladding powder feeding process.

[0040] The Ni3Al / carbide composite material powder provided by the present application is prepared by the plasma rotating electrode method or the vacuum induction melting-inert gas atomization method.

[0041] It should be noted that the plasma rotating electrode method or the vacuum induction melting-inert gas atomization method adopted in the present application is used to prepare the composite material powder according to the chemical composition of the composite material powder to be prepared, and then the plasma rotating electrode method or the vacuum induction melting-inert gas atomization method is used to obtain the pre-alloyed composite material powder.

[0042] The present application also provides a laser cladding method of the Ni3Al / carbide composite material powder, which comprises the following steps:

[0043] Step 1: The Ni3Al / carbide composite material powder is fed to the surface of the steel material by using the coaxial powder feeding method.

[0044] Step 2: The Ni3Al / carbide composite material powder is cladded on the surface of the steel material by using the laser cladding method to form an in-situ self-formed carbide reinforced Ni3Al-based alloy strengthening layer.

[0045] Specifically, the steel material is one of carbon steel, alloy steel, heat-resistant stainless steel and cast iron.

[0046] It should be noted that the carbide Cr7C3 is distributed in the Ni3Al-based alloy powder in an in-situ self-formed manner, which can improve the uniformity of the distribution of Cr7C3 in the alloy powder; when the laser cladding technology is used to prepare the alloy coating, Cr7C3 is re-formed in-situ after melting, which can reduce the size of Cr7C3 and make Cr7C3 more uniformly distributed in the alloy coating.

[0047] Specifically, the coaxial powder feeding amount is 10 g / min to 30 g / min, preferably, the coaxial powder feeding amount is 15 g / min to 20 g / min.

[0048] It should be noted that when the powder feeding amount is low, the dilution rate of the base body (steel material) is high, and the hardness and wear resistance of the Ni3Al-based alloy strengthening layer are greatly reduced; when the powder feeding amount is high, the dilution rate of the base body (steel material) is small, and the metallurgical bonding of the Ni3Al-based alloy strengthening layer and the base body is insufficient, and un-melted powder may appear.

[0049] Specifically, the power of the laser cladding is 1400 to 2600 W, the scanning speed is 0.12 to 0.60 m / min, and the laser beam is a circular spot or a rectangular spot; when the laser beam is a circular spot, the diameter of the circular spot is 2 to 5 mm; when the laser beam is a rectangular spot, the length of the rectangular spot is 5 to 20 mm, and the width is 1 to 6 mm.

[0050] Preferably, the power of the laser cladding is 1600 to 2200 W, the scanning speed is 0.18 to 0.30 m / min, when the laser beam is a circular spot, the diameter of the circular spot is 3 to 4 mm; when the laser beam is a rectangular spot, the length of the rectangular spot is 5 to 10 mm, and the width is 2 to 3 mm.

[0051] It should be noted that when the laser power is small or the scanning speed is fast, the dilution rate of the base body (steel material) is small, and the metallurgical bonding of the Ni3Al-based alloy strengthening layer and the base body is insufficient, and un-melted powder may appear in the cladding layer; when the laser power is large or the scanning speed is slow, the dilution rate of the base body (steel material) is high, and the hardness and wear resistance of the Ni3Al-based alloy strengthening layer are greatly reduced.

[0052] It should be noted that when the spot size is small, the powder falling within the spot size is less, the energy density is high, the dilution rate of the base body (steel material) is high, and the hardness and wear resistance of the Ni3Al-based alloy strengthening layer are greatly reduced; when the spot size is large, the powder falling within the spot size is more, the energy density is reduced, the dilution rate of the base body (steel material) is reduced, and the metallurgical bonding of the Ni3Al-based alloy strengthening layer and the base body is insufficient, and un-melted powder may appear in the cladding layer.

[0053] Specifically, the Ni3Al-based alloy strengthened layer obtained by the laser cladding method comprises a Ni3Al phase, a NiAl phase and a carbide Cr7C3, the carbide Cr7C3 is dispersedly distributed in the Ni3Al-based phase, the thickness of the Ni3Al-based alloy strengthened layer is more than 1.2 mm, preferably 1.2 mm-2.5 mm, the bonding force with the steel material is high (metallurgical bonding), the shear strength of the interface is 400-600 MPa, and specifically, for example, the shear strength of the interface combined with the 42CrMo steel base material is 500-600 MPa. The average hardness of the Ni3Al-based alloy strengthened layer obtained by the laser cladding method is 620-680 HV, and the wear rate is ≤0.8*10 -5 mm 3 / (N·m).

[0054] The application also provides an application of the Ni3Al / carbide composite alloy powder to surface modification of steel parts or nickel-based alloy parts of a heavy-duty diesel engine.

[0055] The Ni3Al / carbide composite material powder, the laser cladding method and the application thereof provided by the application can effectively improve the machining (cutting) performance of the cladding layer, meanwhile, the equivalent atomic ratio of nickel and aluminum is 2.5-2.9, the formation of the NiAl hard phase is promoted, the hardness of the cladding layer is improved, the wear resistance is maintained, and overall, the proportion of the carbide in the cladding layer is reduced, the Ni3Al-based alloy strengthened layer can maintain high hardness and good wear resistance, and the surface performance of the key parts of the heavy-duty diesel engine can be met.

[0056] The preferred embodiments of the application are specifically described below to illustrate the principles of the application, and are not used to limit the scope of the application.

[0057] Example 1

[0058] The morphology of the Ni3Al / carbide composite material powder prepared by the vacuum induction melting-inert gas atomization method is shown in the figure. Figure 1 The particle size of the Ni3Al / carbide alloy powder is 53-124 μm.

[0059] The chemical composition of the Ni3Al / carbide composite material powder in mass percentage is: Al: 9.80%, C: 1.31%, Cr: 18.93%, B: 0.06%, O: 138 ppm, N: 26 ppm, H: 3 ppm, and the balance is Ni, the atomic number ratio of the equivalent of nickel and aluminum is about 2.83, the mass content of the NiAl phase is about 4.3%, and the mass content of the in-situ self-grown carbide Cr7C3 is about 16.5%.

[0060] The Ni3Al / carbide composite powder is used for laser cladding on the surface of 42CrMo steel, laser power is 2000W, scanning speed is 0.18m / min, laser rectangular spot size is 5mm*2mm, coaxial powder feeding amount is 17.5g / min, and in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer is formed.

[0061] The morphology of the in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer prepared in the embodiment is shown in Figure 2 and Figure 3 According to Figure 2 , the Ni3Al-based alloy strengthening layer obtained in the embodiment is crack-free, has compact structure, and the carbide is uniformly distributed, according to Figure 3 , the structure shown in region 1 is Cr7C3, the structure shown in region 2 is Ni3Al, and the structure shown in region 3 is NiAl.

[0062] The thickness of the Ni3Al-based alloy strengthening layer in the embodiment is 2.3mm, the average hardness is 645HV, and the shear strength of the interface is 556MPa. Under dry grinding conditions (surface friction, and the counter-attacking material is gray cast iron), the wear rate of the Ni3Al-based alloy strengthening layer is 0.21*10 -5 mm 3 / (N*m), and the wear rate of the counter-attacking material gray cast iron is 0.29*10 -5 mm 3 / (N*m).

[0063] Example 2

[0064] The particle size range of the Ni3Al / carbide composite powder prepared by the plasma rotating electrode method is 53μm-124μm.

[0065] The chemical composition of the Ni3Al / carbide composite powder in mass percentage is: Al: 9.95%, C: 1.45%, Cr: 19.45%, B: 0.06%, O: 40ppm, N: 28ppm, H: 3ppm, and the balance is Ni, the atomic number ratio of nickel equivalent and aluminum equivalent is about 2.76, the mass content of NiAl phase is about 6.0%, and the mass content of in-situ self-grown carbide Cr7C3 is about 17.0%.

[0066] The Ni3Al / carbide composite powder is used for laser cladding on the surface of vermicular cast iron, laser power is 2200W, scanning speed is 0.18m / min, laser rectangular spot size is 5mm*2mm, coaxial powder feeding amount is 20g / min, and in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer is formed.

[0067] The in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer prepared in the example has no crack, and the carbides are uniformly distributed. The thickness of the Ni3Al-based alloy strengthening layer is 2.5 mm, the average hardness is 665 HV, and the shear strength of the interface is 423 MPa. Under dry friction conditions (surface friction, and the counter-attacking material is gray cast iron), the wear rate of the Ni3Al-based alloy strengthening layer is 0.18×10 -5 mm 3 / (N·m), and the wear rate of the counter-attacking material gray cast iron is 0.37×10 -5 mm 3 / (N·m).

[0068] Example 3

[0069] The particle size range of the Ni3Al / carbide composite material powder prepared by the vacuum induction melting-inert gas atomization method is 53 μm-124 μm.

[0070] The chemical composition of the Ni3Al / carbide composite material powder in mass percentage is: Al: 9.64%, C: 1.19%, Cr: 18.79%, B: 0.05%, O: 172 ppm, N: 37 ppm, H: 4 ppm, and the balance is Ni. The atomic ratio of nickel equivalent and aluminum equivalent is about 2.89, the mass content of NiAl phase is about 2.8%, and the mass content of in-situ self-grown carbide Cr7C3 is about 15.0%.

[0071] The above-mentioned Ni3Al / carbide composite material powder is used for laser cladding on the surface of 42CrMo steel. The laser power is 1600 W, the scanning speed is 0.30 m / min, the diameter size of the circular laser spot is 3 mm, and the coaxial powder feeding amount is 15 g / min. An in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer is formed.

[0072] The in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer prepared in the example has no crack, and the carbides are uniformly distributed. The thickness of the Ni3Al-based alloy strengthening layer is 2.5 mm, the average hardness is 665 HV, and the shear strength of the interface is 423 MPa. Under dry friction conditions (surface friction, and the counter-attacking material is gray cast iron), the wear rate of the Ni3Al-based alloy strengthening layer is 0.18×10 -5 mm 3 / (N·m), and the wear rate of the counter-attacking material gray cast iron is 0.37×10 -5 mm 3 / (N·m).

[0073] Comparative Example 1

[0074] The particle size range of the Ni3Al / carbide composite material powder prepared by the vacuum induction melting-inert gas atomization method is 53 μm-124 μm.

[0075] The chemical composition of the Ni3Al / carbide composite powder is, in mass percentage, Al: 9.22%, C: 1.35%, Cr: 19.01%, B: 0.06%, O: 146 ppm, N: 25 ppm, H: 3 ppm, and the balance of Ni, the atomic ratio of nickel equivalent and aluminum equivalent is about 3, and the mass content of in-situ carbide Cr7C3 is about 16.5%.

[0076] The Ni3Al / carbide composite powder is used for laser cladding on the surface of 42CrMo steel, the laser power is 2000 W, the scanning speed is 0.18 m / min, the laser rectangular spot size is 5 mm x 2 mm, the coaxial powder feeding amount is 17.5 g / min, and the in-situ carbide reinforced Ni3Al-based alloy strengthening layer is formed.

[0077] The in-situ carbide reinforced Ni3Al-based alloy strengthening layer prepared in the comparative example has no cracks, and the carbides are uniformly distributed, the thickness of the Ni3Al-based alloy strengthening layer is 2.3 mm, the average hardness is 546 HV, and the interface shear strength is 538 MPa. Under dry grinding conditions (surface friction, the counter-attacking material is gray cast iron), the wear rate of the Ni3Al-based alloy strengthening layer is 1.19 x 10 -5 mm 3 / (N·m), and the wear rate of the counter-attacking material gray cast iron is 3.05 x 10 -5 mm 3 / (N·m).

[0078] Compared with Example 1, the carbide proportion of the comparative example is the same as that of Example 1, but the atomic ratio of nickel and aluminum is 3, and the NiAl phase is not increased, although the machining performance is improved, but the hardness and wear resistance of the cladding layer are lower.

[0079] Comparative Example 2

[0080] The particle size range of the Ni3Al / carbide composite powder prepared by vacuum induction melting-inert gas atomization method is 53 μm to 124 μm.

[0081] The chemical composition of the Ni3Al / carbide composite powder is, in mass percentage, Al: 8.71%, C: 2.13%, Cr: 25.92%, B: 0.05%, O: 151 ppm, N: 32 ppm, H: 4 ppm, and the balance of Ni, the atomic ratio of nickel equivalent and aluminum equivalent is about 2.83, the mass content of NiAl phase is about 3.8%, and the mass content of in-situ carbide Cr7C3 is about 25%.

[0082] The Ni3Al / carbide composite powder is used for laser cladding on the surface of 42CrMo steel, laser power is 2000 W, scanning speed is 0.18 m / min, laser rectangular spot size is 5 mm*2 mm, coaxial powder feeding amount is 17.5 g / min, and an in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer is formed.

[0083] The in-situ self-grown carbide reinforced Ni3Al-based alloy strengthening layer prepared in the comparative example has uniform carbide distribution, a thickness of 2.1 mm, an average hardness of 729 HV, and an interface shear strength of 517 MPa, but cracks appear in the cladding layer, and crack tendency is obviously increased. The crack-free cladding layer region is selected to prepare a friction and wear sample, under dry friction conditions (surface friction, and the counter-attacking material is gray cast iron), the wear rate of the laser cladding layer is 0.20*10 -5 mm 3 / (N*m), and the wear rate of the counter-attacking material gray cast iron is 0.72*10 -5 mm 3 / (N*m).

[0084] Compared with example 1, the nickel-aluminum atomic ratio of the comparative example and example 1 is the same, but the mass content of in-situ self-grown carbide Cr7C3 is about 25%, although high hardness and good wear resistance are maintained, but the high hardness carbide strengthening phase ratio is relatively high, which leads to poor machining (cutting) performance of the cladding layer.

[0085] Specifically, the performance of examples 1-3 and comparative examples 1-2 provided by the present application is shown in Table 1.

[0086] Table 1 Performance of examples 1-3 and comparative examples 1-2

[0087]

[0088] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any change or replacement that can be easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered in the protection scope of the present application.

Claims

1. A Ni3Al / carbide composite powder, characterized by, The chemical composition in percentage by mass is: Al: 9.5%-10.0%, C: 1.1%-1.6%, Cr: 18.0%-19.5%, B: 0.05%-0.07%, O≤200ppm, N≤50ppm, H≤10ppm, and the balance of Ni; In the Ni3Al / carbide composite powder, the atomic ratio of nickel equivalent and aluminum equivalent is 2.5-2.9, the Ni3Al / carbide composite powder comprises a Ni3Al phase and a NiAl phase, and the mass content of the NiAl phase is 2.5%-8.5%; the hardness of the Ni3Al phase is 300-400HV, the hardness of the NiAl phase is 500-700HV, and the hardness of the Cr7C3 type carbide is more than 1200HV; The calculation principle of the atomic number of nickel equivalent is: The calculation principle of the atomic number of aluminum equivalent is: wherein Cr Ni3Al溶 is 4% to 10%, Ni represents the mass percentage of the Ni element in the Ni3Al / carbide composite material powder, and Al represents the mass percentage of the Al element in the Ni3Al / carbide composite material powder; The carbide structure of the Ni3Al / carbide composite powder is Cr7C3, and the mass content of the Cr7C3 is 13%-18%, which is dispersedly distributed in the Ni3Al base phase; The particle size range of the Ni3Al / carbide composite powder is 53μm-124μm.

2. A laser cladding method of the Ni3Al / carbide composite material powder according to claim 1, characterized by, The method comprises the following steps: Step 1: using a coaxial powder feeding method to feed the Ni3Al / carbide composite powder to the surface of a steel material; Step 2: using a laser cladding method to clad the Ni3Al / carbide composite powder on the surface of the steel material to form an in-situ self-grown carbide reinforced Ni3Al base alloy strengthening layer.

3. The laser cladding method according to claim 2, characterized in that, The coaxial powder feeding amount of the coaxial powder feeding method is 10g / min-30g / min.

4. The laser cladding method according to claim 2, characterized in that, The power of the laser cladding is 1400W-2600W, and the scanning speed is 0.12m / min-0.60m / min.

5. The laser cladding method according to claim 2, wherein The laser beam of the laser cladding method is a circular spot or a rectangular spot.

6. An in-situ self-grown carbide reinforced Ni3Al base alloy strengthening layer prepared from the Ni3Al / carbide composite powder according to claim 1, characterized in that, The in-situ self-grown carbide reinforced Ni3Al base alloy strengthening layer is formed on the surface of a steel material by a laser cladding method, the Ni3Al base alloy strengthening layer comprises a Ni3Al phase, a NiAl phase and a carbide Cr7C3, and the carbide Cr7C3 is dispersedly distributed in the Ni3Al phase, The average hardness of the Ni3Al-based alloy reinforced layer is 620–680 HV, and the wear rate is ≤0.8×10⁻⁶. -5 mm 3 / (N The shear strength of the interface between the steel material and the metal is 400~600MPa.

7. The in-situ self-generated carbide reinforced Ni3Al-based alloy strengthened layer according to claim 6, wherein, The Ni3Al base alloy strengthening layer is prepared by the laser cladding method according to any one of claims 3-5.

8. The in-situ self-generated carbide reinforced Ni3Al-based alloy strengthened layer according to claim 6, wherein, The steel material is one of carbon steel, alloy steel, heat-resistant stainless steel and cast iron.

9. Use of a Ni3Al / carbide composite powder, characterized in that The Ni3Al / carbide composite powder according to claim 1 is used for surface modification of a steel or nickel base alloy part of a heavy-duty diesel engine.

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