1. The method for the additive manufacturing of the nickel-based alloy is characterized by comprising the following steps of:

(1) preparing cladding powder:

the nickel-based powder comprises, by mass, 39-41% of Ti, 1.7-1.9% of Cr, 1.5-1.7% of Cu, 1.0-1.2% of Si, 0.6-1.0% of composite rare earth, 0.2-0.4% of C, 0.2-0.4% of B, 0.08-0.12% of V, 0.01-0.03% of Sr and the balance of Ni, and has a particle size of 100-240 meshes and a spherical or nearly spherical powder shape;

after preparing the nickel-based powder according to the proportion, mixing the powder in a vacuum ball mill for 3-5 min; then, preserving heat for 6-8 min in a vacuum insulation box with the temperature of 50-60 ℃;

(2) the laser cladding process comprises the following steps:

the method comprises the following steps of utilizing an optical fiber laser to perform laser cladding additive manufacturing on a nickel-based alloy component in an argon protective atmosphere in a coaxial powder feeding mode, wherein the cladding layer thickness, the laser power, the scanning speed and the powder feeding speed are selected according to the following model calculation:

wherein, Y, cladding layer thickness, unit: um;

x₁laser power, unit: w;

x₂scanning speed, unit: mm/min;

x₃powder feeding speed, unit: g/min;

(3) the laser shock process comprises the following steps:

a high-energy lamp pump solid laser system is adopted, a restraint layer is K9 glass, an absorption layer is aluminum foil, and the selection of residual tensile stress after laser impact on a cladding layer, surface roughness after laser impact and laser impact energy is calculated according to the following model:

Z＝-120.129cos(-0218a₁ ²)-121.135cos(47.067a₂ ²)-298.704

wherein, Z, residual tensile stress, unit: MPa;

a₁energy of laser shock, unit: j;

a₂surface roughness after laser shock, unit: the um is the sum of the total weight of the particles,

(4) and (4) repeating the steps (2) to (3) until the nickel-based alloy component is repaired or manufactured.

2. The additive manufacturing method of a nickel-based alloy according to claim 1, wherein in the step (1), the chemical composition of the nickel-based powder is, in mass percent, 40% of Ti, 1.8% of Cr, 1.6% of Cu, 1.1% of Si, 0.8% of rare earth complex, 0.3% of C, 0.3% of B, 0.1% of V, 0.02% of Sr, and the balance being Ni.

3. The method for the additive manufacturing of the nickel-based alloy according to the claim 1 or 2, wherein in the step (1), the chemical composition of the composite rare earth is as follows: 30-36% of La, 30-36% of Eu, 5-7% of Nd, 5-7% of Pm, 1-3% of Pr, 1-3% of Gd and the balance of Ce.

4. The method for the additive manufacturing of the nickel-based alloy according to claim 3, wherein in the step (1), the chemical composition of the composite rare earth is as follows: 33% of La, 33% of Eu, 6% of Nd, 6% of Pm, 2% of Pr, 2% of Gd, and the balance Ce.

5. The additive manufacturing method of the nickel-based alloy according to claim 1, wherein in the step (2), the laser cladding process parameters are as follows: the diameter of the light spot is 3 mm; the lap joint rate: 40 percent.

6. The additive manufacturing method of nickel-base alloy according to claim 1, wherein in the step (2), the thickness Y of the cladding layer is less than 1000 um.

7. The additive manufacturing method of nickel-base alloy according to claim 1, wherein in the step (3), the thickness of the aluminum foil is 0.3 mm; the laser shock process parameters are as follows: the diameter of the light spot: 3.0 mm; the lap joint rate: 50 percent; pulse width: 20 ns; wavelength: 1064 nm.

8. The additive manufacturing method of nickel-base alloy according to claim 1, wherein in the step (3), the residual tensile stress after laser shock is less than 80 MPa.

9. The method of additive manufacturing of nickel-base alloys according to claim 1, wherein in step (3), the surface roughness after laser shock is less than Ra 0.6 um.

Background

The nickel-based alloy has excellent mechanical properties, high-temperature properties and other characteristics, and is widely applied in recent years, particularly in the fields of aerospace and aviation, and is mainly used for manufacturing high-temperature components such as engines, turbines and the like. The working conditions of the components are extremely complex and severe, and the requirements on the comprehensive performance of the components are extremely high. With the advancement of science and technology and the increase of human living demand, the traditional manufacturing methods of casting and machining can just not satisfy the growing high-quality requirements of the components, and the additive manufacturing technology has significant advantages in manufacturing complex parts.

Additive Manufacturing (AM), commonly known as 3D printing, builds up materials layer by means of extrusion, sintering, melting, photocuring, jetting, etc. through computer modeling design and control systems to manufacture various articles, and is particularly suitable for Manufacturing components with complex shapes. With the rapid development of laser application and the reduction of laser system cost, laser technology is widely applied in the fields of automobiles, aviation, aerospace, military, national defense and the like. Among them, laser cladding has been regarded as important because the prepared metal coating is unlimited and can realize the diversified potentials of material processing such as repair and additive manufacturing of components.

At present, laser cladding additive manufacturing of nickel-based alloy still has many problems, because laser cladding is a fast melting and fast solidifying process, because energy input is high, temperature gradient is big, cooling speed is fast and material properties have differences, the molten pool can produce higher internal stress in the cooling and solidifying process, directly leads to the cladding layer can produce great residual stress and make the part warp, ftracture. In addition, repeated laser lap cladding and laser multilayer additive cladding also easily generate coarse dendritic crystal structures and even segregation phenomena, and the structural rigidity, static load strength, fatigue strength and the like of the parts are seriously influenced. The methods for improving the problems mainly comprise: preheating a base material, optimizing process parameters, carrying out heat treatment, adding a plastic material into a cladding layer and the like. However, these methods require additional production steps and increase production costs. Therefore, the invention develops a method for additive manufacturing of the nickel-based alloy.

Disclosure of Invention

The invention develops a method for additive manufacturing of nickel-based alloy, which comprises the steps of carrying out laser cladding treatment on the surface of a component, then carrying out laser shock treatment on the component, and greatly improving the thermal fatigue property of the component after the component and the component are coordinated and strengthened, prolonging the service life of the component and expanding the application field of the component. The method comprises the following specific steps:

(1) and preparing cladding powder. The nickel-based powder comprises, by mass, 39-41% of Ti, 1.7-1.9% of Cr, 1.5-1.7% of Cu, 1.0-1.2% of Si, 0.6-1.0% of composite rare earth, 0.2-0.4% of C, 0.2-0.4% of B, 0.08-0.12% of V, 0.01-0.03% of Sr, and the balance of Ni, and has a particle size of 100-240 meshes and a spherical or nearly spherical powder shape. Wherein, the chemical components of the composite rare earth are as follows: 30-36% of La, 30-36% of Eu, 5-7% of Nd, 5-7% of Pm, 1-3% of Pr, 1-3% of Gd and the balance of Ce. Before the laser cladding process, the powder needs to be mixed in a vacuum ball mill for 3-5 min, so that the powder is uniformly mixed; and then preserving heat in a vacuum insulation box at the temperature of 50-60 ℃ for 6-8 min to remove the influence of moisture.

Among these, the above-mentioned nickel-based powder preferably has the following composition: the chemical components by mass percent are 40 percent of Ti, 1.8 percent of Cr, 1.6 percent of Cu, 1.1 percent of Si, 0.8 percent of composite rare earth, 0.3 percent of C, 0.3 percent of B, 0.1 percent of V, 0.02 percent of Sr and the balance of Ni.

Wherein, the preferable components of the composite rare earth are as follows: 33% of La, 33% of Eu, 6% of Nd, 6% of Pm, 2% of Pr, 2% of Gd, and the balance Ce.

(2) And (3) laser cladding process. And performing laser cladding additive manufacturing by using a fiber laser in a coaxial powder feeding mode under the argon protection atmosphere. The laser cladding process parameters are as follows: the diameter of the light spot is 3 mm; the lap joint rate: 40 percent. Ensuring that the thickness (Y, unit: um) of the cladding layer is less than 1000um and the laser power (x) is ensured to ensure the subsequent laser shock treatment effect₁The unit: w), scanning speed (x)₂The unit: mm/min) and powder feed rate (x)₃The unit: g/min) should be selected according to the following model:

(3) and (3) laser shock processing. A high-energy lamp pump solid laser system is adopted, a restraint layer is K9 glass, and an absorption layer is an aluminum foil with the thickness of 0.3 mm. The laser shock process parameters are as follows: the diameter of the light spot: 3.0 mm; the lap joint rate: 50 percent; pulse width: 20 ns; wavelength: 1064 nm. In order to reduce the residual tensile stress on the surface of the cladding layer after laser cladding so as to eliminate the generation of defects such as microcracks and the like in the cladding layer, the residual tensile stress (Z, unit: MPa) after laser impact on the cladding layer is less than 80MPa, and the surface roughness (a) after laser impact is realized₂The unit: um) Ra<0.6um, energy of laser shock (a)₁The unit: J) should be calculated according to the following model:

Z＝-120.129cos(-0.218a₁ ²)-121.135cos(47.067a₂ ²)-298.704

(4) and (4) repeating the steps (2) to (3) until the nickel-based alloy component is repaired or manufactured.

The invention has the beneficial effects that:

the laser cladding powder used by the invention is shape memory alloy powder, and the shape memory alloy has stress self-adaptive property, namely when the alloy is under the action of external stress, the positive and negative phase transformation of epsilon martensite can be induced by the stress, and the phase transformation deformation can be used for relaxing the residual stress in the cladding layer, thereby reducing the cracking sensitivity of the cladding layer and the deformation problem of workpieces. In addition, the cladding layer is subjected to laser shock treatment, so that residual tensile stress generated during cladding can be consumed by strong impact force generated by laser shock waves, and even residual compressive stress is prefabricated; but also can refine the structural crystal grains of the cladding layer and avoid generating coarse columnar crystals in the repeated cladding process, thereby effectively improving the performance of the material increase manufacturing nickel-based alloy component.

Detailed Description

The abrasion test is carried out on an MMU-5GA microcomputer controlled high-temperature friction abrasion tester. Sample size: a pin sample of 4.8mm in diameter by 12.7mm was machined from GCr15 steel to form a disc sample of 54mm in diameter by 8mm in diameter. Each sample is cleaned in an ultrasonic cleaning machine before and after the abrasion test, the cleaning liquid is 20% acetone solution, and the cleaning time is 6 min. And then drying the sample in a 50 ℃ heat preservation furnace for 20min to reduce the surface pollution degree of the sample to the maximum extent. And finally, weighing the sample after the sample is cooled to room temperature. Weighing was carried out using an electronic balance of the MA110 type with an accuracy of 0.1 mg. Abrasion resistance is expressed in terms of loss of abrasion. Dry sliding friction abrasion is adopted, the experiment temperature is 25 ℃ and 400 ℃, the load is 150N, the rotating speed is 50r/min, and the abrasion time is 30 min.

Example 1

The nickel-based alloy is selected from commercially available Inconel 718 alloy. Additive manufacturing is carried out according to the following steps:

step (1): and preparing cladding powder. The nickel-based powder comprises, by mass, 39% of Ti, 1.7% of Cr, 1.5% of Cu, 1.0% of Si, 0.6% of composite rare earth, 0.2% of C, 0.2% of B, 0.08% of V, 0.01% of Sr and the balance of Ni, and has a powder particle size of 100-240 meshes. Wherein, the chemical components of the composite rare earth are as follows: 30% of La, 30% of Eu, 5% of Nd, 5% of Pm, 1% of Pr, 1% of Gd, and the balance of Ce. Before the laser cladding process, the powder needs to be ground and mixed in a vacuum ball mill for 3-5 min, so that the powder is uniformly mixed and is spherical or nearly spherical; and then preserving heat in a vacuum insulation box at the temperature of 50-60 ℃ for 6-8 min to remove the influence of moisture.

Step (2): and (3) laser cladding process. And performing laser cladding additive manufacturing by using a fiber laser in a coaxial powder feeding mode under the argon protection atmosphere. The laser cladding process parameters are as follows: the diameter of the light spot is 3 mm; the lap joint rate: 40 percent. In order to ensure the subsequent laser shock treatment effect and ensure that the thickness of the cladding layer is less than 1000um, the laser power is obtained according to the model: 1500W; scanning speed: 400 mm/min; powder feeding speed: 14 g/min.

And (3) performing a laser shock process. A high-energy lamp pump solid laser system is adopted, a restraint layer is K9 glass, and an absorption layer is an aluminum foil with the thickness of 0.3 mm. The laser shock process parameters are as follows: the diameter of the light spot: 3.0 mm; the lap joint rate: 50 percent; pulse width: 20 ns; wavelength: 1064 nm. In order to reduce the residual tensile stress on the surface of the cladding layer after laser cladding so as to eliminate the generation of defects such as microcracks in the cladding layer and the like, the residual tensile stress is less than 80MPa after laser impacts on the cladding layer, and the surface roughness Ra is less than 0.6um after the laser impacts, the energy of the laser impact is obtained according to a model: 5J. The above steps are repeated for 8 times, and then the abrasion test of the specific embodiment is performed on the nickel-based alloy subjected to the laser cladding and laser shock treatment, and the results are shown in table 1.

Example 2

The nickel-based alloy is selected from commercially available Inconel 718 alloy. Additive manufacturing is carried out according to the following steps:

step (1): and preparing cladding powder. The nickel-based powder comprises, by mass, 41% of Ti, 1.9% of Cr, 1.7% of Cu, 1.2% of Si, 1.0% of composite rare earth, 0.4% of C, 0.4% of B, 0.12% of V, 0.03% of Sr and the balance of Ni, and has a particle size of 100-240 meshes. Wherein, the chemical components of the composite rare earth are as follows: 36% of La, 36% of Eu, 7% of Nd, 7% of Pm, 3% of Pr, 3% of Gd, and the balance of Ce. Before the laser cladding process, the powder needs to be ground and mixed in a vacuum ball mill for 3-5 min, so that the powder is uniformly mixed and is spherical or nearly spherical; and then preserving heat in a vacuum insulation box at the temperature of 50-60 ℃ for 6-8 min to remove the influence of moisture.

Step (2): and (3) laser cladding process. And performing laser cladding additive manufacturing by using a fiber laser in a coaxial powder feeding mode under the argon protection atmosphere. The laser cladding process parameters are as follows: the diameter of the light spot is 3 mm; the lap joint rate: 40 percent. In order to ensure the subsequent laser shock treatment effect and ensure that the thickness of the cladding layer is less than 1000um, the laser power is obtained according to the model: 1500W; scanning speed: 400 mm/min; powder feeding speed: 14 g/min.

And (3) performing a laser shock process. A high-energy lamp pump solid laser system is adopted, a restraint layer is K9 glass, and an absorption layer is an aluminum foil with the thickness of 0.3 mm. The laser shock process parameters are as follows: the diameter of the light spot: 3.0 mm; the lap joint rate: 50 percent; pulse width: 20 ns; wavelength: 1064 nm. In order to reduce the residual tensile stress on the surface of the cladding layer after laser cladding so as to eliminate the generation of defects such as microcracks in the cladding layer and the like, the residual tensile stress is less than 80MPa after laser impacts on the cladding layer, and the surface roughness Ra is less than 0.6um after the laser impacts, the energy of the laser impact is obtained according to a model: 5J. The above steps are repeated for 8 times, and then the abrasion test of the specific embodiment is performed on the nickel-based alloy subjected to the laser cladding and laser shock treatment, and the results are shown in table 1.

Example 3

The nickel-based alloy is selected from commercially available Inconel 718 alloy. Additive manufacturing is carried out according to the following steps:

step (1): and preparing cladding powder. The nickel-based powder comprises, by mass, 40% of Ti, 1.8% of Cr, 1.6% of Cu, 1.1% of Si, 0.8% of composite rare earth, 0.3% of C, 0.3% of B, 0.1% of V, 0.02% of Sr and the balance of Ni, and has a particle size of 100-240 meshes. Wherein, the chemical components of the composite rare earth are as follows: 33% of La, 33% of Eu, 6% of Nd, 6% of Pm, 2% of Pr, 2% of Gd, and the balance Ce. Before the laser cladding process, the powder needs to be ground and mixed in a vacuum ball mill for 3-5 min, so that the powder is uniformly mixed and is spherical or nearly spherical; and then preserving heat in a vacuum insulation box at the temperature of 50-60 ℃ for 6-8 min to remove the influence of moisture.

Step (2): and (3) laser cladding process. And performing laser cladding additive manufacturing by using a fiber laser in a coaxial powder feeding mode under the argon protection atmosphere. The laser cladding process parameters are as follows: the diameter of the light spot is 3 mm; the lap joint rate: 40 percent. In order to ensure the subsequent laser shock treatment effect and ensure that the thickness of the cladding layer is less than 1000um, the laser power is obtained according to the model: 1500W; scanning speed: 400 mm/min; powder feeding speed: 14 g/min.

And (3) performing a laser shock process. A high-energy lamp pump solid laser system is adopted, a restraint layer is K9 glass, and an absorption layer is an aluminum foil with the thickness of 0.3 mm. The laser shock process parameters are as follows: the diameter of the light spot: 3.0 mm; the lap joint rate: 50 percent; pulse width: 20 ns; wavelength: 1064 nm. In order to reduce the residual tensile stress on the surface of the cladding layer after laser cladding so as to eliminate the generation of defects such as microcracks in the cladding layer and the like, the residual tensile stress is less than 80MPa after laser impacts on the cladding layer, and the surface roughness Ra is less than 0.6um after the laser impacts, the energy of the laser impact is obtained according to a model: 5J. The above steps are repeated for 8 times, and then the abrasion test of the specific embodiment is performed on the nickel-based alloy subjected to the laser cladding and laser shock treatment, and the results are shown in table 1.

Comparative example 1

A commercially available Inconel 718 alloy was selected as the nickel-based alloy, and subjected to an abrasion test according to a specific embodiment, and the results are shown in table 1.

Comparative example 2

The nickel-based alloy is selected from commercially available Inconel 718 alloy, and is subjected to laser cladding treatment.

Step (1): and preparing cladding powder. The nickel-based powder comprises, by mass, 40% of Ti, 1.8% of Cr, 1.6% of Cu, 1.1% of Si, 0.8% of composite rare earth, 0.3% of C, 0.3% of B, 0.1% of V, 0.02% of Sr and the balance of Ni, and has a particle size of 100-240 meshes. Wherein, the chemical components of the composite rare earth are as follows: 33% of La, 33% of Eu, 6% of Nd, 6% of Pm, 2% of Pr, 2% of Gd, and the balance Ce. Before the laser cladding process, the powder needs to be ground and mixed in a vacuum ball mill for 3-5 min, so that the powder is uniformly mixed and is spherical or nearly spherical; and then preserving heat in a vacuum insulation box at the temperature of 50-60 ℃ for 6-8 min to remove the influence of moisture.

Step (2): and (3) laser cladding process. And performing laser cladding additive manufacturing by using a fiber laser in a coaxial powder feeding mode under the argon protection atmosphere. The laser cladding process parameters are as follows: the diameter of the light spot is 3 mm; the lap joint rate: 40 percent. In order to ensure the subsequent laser shock treatment effect and ensure that the thickness of the cladding layer is less than 1000um, the laser power is obtained according to the model: 1500W; scanning speed: 400 mm/min; powder feeding speed: 14 g/min. The above steps are repeated for 8 times, and then the wear test of the specific embodiment is performed on the nickel-based alloy subjected to the laser cladding treatment, and the results are shown in table 1.

Comparative example 3

The nickel-based alloy was selected from commercially available Inconel 718 alloy and subjected to laser shock treatment. A high-energy lamp pump solid laser system is adopted, a restraint layer is K9 glass, and an absorption layer is an aluminum foil with the thickness of 0.3 mm. The laser shock process parameters are as follows: the diameter of the light spot: 3.0 mm; the lap joint rate: 50 percent; pulse width: 20 ns; wavelength: 1064 nm. In order to reduce the residual tensile stress on the surface of the cladding layer after laser cladding so as to eliminate the generation of defects such as microcracks in the cladding layer and the like, the residual tensile stress is less than 80MPa after laser impacts on the cladding layer, and the surface roughness Ra is less than 0.6um after the laser impacts, the energy of the laser impact is obtained according to a model: 5J. The above steps were repeated 8 times, and then the abrasion test of the embodiment was performed on the nickel base alloy subjected to the laser shock treatment, and the results are shown in table 1.

TABLE 1 Friction and wear Properties of Nickel-base alloys prepared by different Processes

As can be seen from table 1: the example is the Inconel 718 alloy which is currently in widespread use. After the nickel-based alloy is strengthened by the patented process, the frictional wear performance of the nickel-based alloy is greatly improved, and particularly the improvement effect of the frictional wear performance at 400 ℃ is obvious. Comparative example 1, which is not treated Inconel 718 alloy, has poor wear resistance. Comparative example 2 is a laser clad Inconel 718 alloy and comparative example 3 is a laser shock treated Inconel 718 alloy. From the experimental results of table 1, it can be found that: although the wear resistance of the nickel-based alloy material can be improved to a certain extent by the laser cladding and laser shock methods, the effect is not obvious. For the laser cladding treatment method, microcracks are easily generated in the cladding layer and are influenced by heat transmission and stress strain in the laser cladding process, and columnar crystals, segregation, intermetallic compounds with high brittleness and high residual stress are easily formed in the cladding layer and a fusion area and a heat affected area which are combined with the base material, so that the strengthening effect of the laser cladding is weakened. For the laser shock treatment method, the effects of grain refinement and prefabricated residual compressive stress are only exerted on the surface of the alloy, and the action range is limited. In comparison, by adopting the composite strengthening process method disclosed by the invention, the problems of microcracks and coarse grains in the cladding layer and the combination area between the cladding layer and the matrix can be effectively improved, so that the performance of the nickel-based alloy material is favorably improved.

In a word, the laser cladding and laser shock composite strengthening treatment provided by the invention is an additive manufacturing method for effectively improving the performance of the nickel-based alloy.