A method for predicting failure mechanisms of particle-reinforced metal matrix composites based on particle size effects

Abstract

The present invention discloses a method for predicting the failure mechanism of a particle-reinforced metal-based composite material based on a particle scale effect. By comparing the maximum stress borne by the particle with the critical maximum fracture stress of the particle under macroscopic tensile stress conditions, it is judged whether the failure mechanism is only interface debonding or whether the particle fracture will be caused by interface debonding. If the microscopic failure mechanism of the particle-reinforced metal-based composite material is first interface debonding and then particle fracture, but because the microscopic mechanism of particle fracture is not beneficial to the fracture toughness of the particle-reinforced metal-based composite material, it is necessary to adjust the process parameters at this time; if the predicted microscopic failure mechanism of the particle-reinforced metal-based composite material is interface debonding, and the interface debonding failure mechanism is beneficial to the fracture toughness of the particle-reinforced metal-based composite material, it is only necessary to continue to optimize the process parameters.

Description

[Technical field]

[0001] The invention belongs to the technical field of metal materials and relates to a method for predicting the failure mechanism of particle-reinforced metal-based composite materials based on particle size effect. [Background technology]

[0002] Metal matrix composites are a new type of material that is made of metal or alloy as the matrix and particles or fibers as the reinforcement phase. It combines the advantages of good plasticity and toughness of metals and high strength and high rigidity of the reinforcement phase, thus showing physical and mechanical properties different from those of the matrix material. This type of material has higher compression resistance, shear resistance, impact resistance, friction resistance and high temperature tolerance than the matrix, and also has incomparable designability over traditional alloy materials.

[0003] A large number of studies have shown that the mechanical properties of particle-reinforced metal matrix composites are affected by many factors, such as preparation process, component material properties, particle volume fraction, size, shape, distribution, particle-matrix interface bonding state, and heat treatment process. Due to the wide variety of materials and the fact that their performance is affected by various factors, the cost of providing a design basis for practical applications through experimental research performance is high, and the design cycle is long. Therefore, in recent decades, a large number of researchers have tried to predict the performance of particle-reinforced metal matrix composites from a theoretical perspective, and have made a lot of efforts to improve the preparation process and reduce the design cost and cycle. [Summary of the invention]

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for predicting the failure mechanism of particle-reinforced metal matrix composites based on particle size effect, so as to accurately predict the failure mechanism of particle-reinforced metal matrix composites.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for predicting the failure mechanism of particle-reinforced metal matrix composites based on particle size effect. Under the condition that the metal matrix composite is subjected to tensile stress, the maximum stress (σ p ) max The critical particle fracture stress σ is determined based on the particle size and fracture toughness of the metal matrix composite. cr ;

[0007] If (σ p ) max Greater than σ cr , then the metal matrix composite material will first undergo interface debonding, followed by particle fracture;

[0008] If (σ p )max Less than σ cr , then only interface debonding occurs in the metal matrix composite material.

[0009] A further improvement of the present invention is:

[0010] Preferably, the maximum stress (σ p ) max The calculation formula is:

[0011]

[0012] in, is the critical plastic strain, μ * is the elastic factor that is inconsistent with the metal matrix and particle plasticity, f is the particle volume fraction, Φ * is the intermediate parameter of the damage function, and K is the strength coefficient of the metal matrix.

[0013] Preferably, the elastic factor μ of the metal matrix and the particle plasticity is not coordinated * The calculation formula is:

[0014]

[0015] Among them, μ M is the shear modulus of the metal matrix, μ P is the shear modulus of the particle, and γ is the Eshelby factor.

[0016] Preferably, the Eshelby factor γ of the spherical particles is expressed as 1-2(4-5ν) / 15(1-ν).

[0017] Preferably, the intermediate parameter Φ of the damage function * The calculation formula is:

[0018]

[0019] Preferably, the critical particle fracture stress σ cr The calculation formula is:

[0020]

[0021] Among them, K ΙC is the fracture toughness of the particle, and d is the particle diameter.

[0022] Preferably, if (σ p ) max Greater than σ cr , then by adjusting the particle volume fraction, adjust (σ p ) max , to (σ p ) max Less than σcr ; if (σ p ) max Less than σ cr , by adjusting the particle volume fraction, adjust (σ p ) max , until (σ p ) max and σ cr The difference between them is ≤5MPa.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention discloses a method for predicting the failure mechanism of a particle-reinforced metal matrix composite material based on a particle scale effect. By comparing the maximum stress borne by the particle with the critical fracture stress of the particle under macroscopic tensile stress conditions, it is determined whether the failure mechanism is only interface debonding or whether the particle fracture is caused by interface debonding. If the microscopic failure mechanism of the particle-reinforced metal matrix composite material is interface debonding first and then particle fracture, but the microscopic mechanism of particle fracture is not beneficial to the fracture toughness of the particle-reinforced metal matrix composite material, it is necessary to adjust the process parameters at this time; if the predicted microscopic failure mechanism of the particle-reinforced metal matrix composite material is interface debonding, and the interface debonding failure mechanism is beneficial to the fracture toughness of the particle-reinforced metal matrix composite material, it is only necessary to continue to optimize the process parameters. The present invention provides a theoretical basis for the design of process parameters such as the volume fraction and size of particles in the preparation process of the particle-reinforced metal matrix composite material. Thereby achieving the purpose of scientifically designing the preparation process to improve the mechanical properties of the particle-reinforced metal matrix composite material.

Brief Description of the Drawings

[0025] Figure 1 This is a schematic diagram of the principle of the criterion for determining the microscopic failure mechanism of particle-reinforced metal matrix composite materials in Example 1. [Specific implementation method]

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0027] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] A method for predicting failure mechanisms of particle-reinforced metal matrix composites based on particle size effects comprises the following steps:

[0029] Step 1: Determine the particle type, metal matrix material type, particle volume fraction f, Poisson's ratio ν of the reinforced particles, and the shear modulus μ of the particles. P , the shear modulus of the metal matrix μ M , Poisson's ratio ν of the particle, and the elastic factor of the incompatibility between the metal matrix and the particle plasticity:

[0030]

[0031] The Eshelby factor γ for spherical particles is expressed as 1-2(4-5ν) / 15(1-ν); the volume fraction of the particles is the Poisson's ratio ν of the reinforcing particles, the shear modulus μ of the particles, which is known in the preparation process of the metal matrix composite material. P , the shear modulus of the metal matrix μ M , and the Poisson's ratio ν of the particles are known parameters obtained from books.

[0032] Step 2: Determine the yield stress σ0 and critical plastic strain of the metal matrix material The strength coefficient K of the metal matrix material is used to calculate the intermediate parameter Φ of the damage function. *

[0033]

[0034] Among them, the yield stress σ0 of the metal matrix material and the critical plastic strain The strength coefficient K of the metal matrix material is a known parameter obtained from books.

[0035] Step 3: Determine the fracture toughness K of the particle ΙC , particle diameter d, calculate the critical particle fracture stress considering the particle size effect [A. Borbély, H. Biermann, and O. Hartmann, FE investigation of the effect of particle distribution on the uniaxial stress-strain behaviour of particulate reinforced metal-matrix composites, Materials Science & Engineering A 313 (2001), pp. 34-45].

[0036]

[0037] Among them, the fracture toughness K of the particle ΙC It is an inherent property of the particles. It can be found in relevant books that the particle diameter d is the property of the metal matrix composite material itself.

[0038] Step 4: From the critical plastic strain of the metal Strength coefficient K of metal matrix material, intermediate parameter Φ of damage function * , particle volume fraction f, elastic factor μ of the incompatibility between metal matrix and particle plasticity * The maximum particle bearing stress is determined as:

[0039]

[0040] Step 5: convert the above obtained (σ p ) max With σ cr The value is substituted into the criterion for determining the microscopic failure mechanism of particle reinforced metal matrix composites considering the scale effect.

[0041]

[0042] In the above judgment formula (5), if the predicted Under the condition of macroscopic tensile stress, the microscopic failure mechanism of particle reinforced metal matrix composites is first interface debonding and then particle fracture. However, since the microscopic mechanism of particle fracture is not beneficial to the fracture toughness of particle reinforced metal matrix composites, the process parameters at this time need to be adjusted. Under the condition of macroscopic tensile stress, the microscopic failure mechanism of particle reinforced metal matrix composites is interface debonding, which is beneficial to the fracture toughness of particle reinforced metal matrix composites. Therefore, this process parameter can be used for preparation, but it needs to be further optimized until If it is close to 1 but not equal to 1, then the process parameters at this time are optimal.

[0043] The present invention adopts a particle stress model σ based on the interface damage mechanism and kinematic strengthening mechanism of particle reinforced metal matrix composite materials p and the critical particle fracture stress σ considering the scale effect cr The maximum normal stress fracture criterion is used for the coupling. If the maximum stress (σ p ) max Greater than σ cr , then the metal matrix composite material will first undergo the microscopic failure mechanism of interface debonding and then the microscopic failure mechanism of particle fracture under the condition of macroscopic tensile stress. If the predicted stress carried by the particle (σ p ) max Less than σ cr , then the metal matrix composite material will only undergo microscopic failure mechanism of interface debonding under macroscopic tensile stress.

[0044] Under macroscopic tensile stress, the stress model σ borne by particles based on the interface damage mechanism and kinematic strengthening mechanism of particle reinforced metal matrix composites is p for:

[0045]

[0046] in, is the critical plastic strain, Φ is the plastic strain of the metal matrix ε p The interface damage function is related to the strength coefficient, σ0 is the yield stress of the metal matrix, f is the particle volume fraction, μ * It is the elastic factor that is inconsistent with the plasticity of the metal matrix and particles. * Shear modulus μ with metal matrix M , the shear modulus of the particle μ P Correlated with Eshelby factor γ.

[0047] The method for predicting the microscopic failure mechanism of particle-reinforced metal matrix composites based on particle size effect obtained by the above method is:

[0048] In the process of preparing particle reinforced metal matrix composites, the process parameters such as particle volume fraction f, yield stress σ0 of the metal matrix, particle diameter d and related performance parameters such as critical plastic strain are first determined. Poisson's ratio ν of the particle, shear modulus μ of the particle P , the shear modulus of the metal matrix μ M , the fracture toughness K of the particle ΙC Substitute it into the above-mentioned criterion for determining the microscopic failure mechanism of particle reinforced metal matrix composites considering the scale effect.

[0049] If the predicted Under the condition of macroscopic tensile stress, the microscopic failure mechanism of particle-reinforced metal matrix composites is first interface debonding and then particle fracture. However, because the microscopic mechanism of particle fracture is not beneficial to the fracture toughness of particle-reinforced metal matrix composites, the process parameters at this time need to be adjusted.

[0050] If the predicted Under the condition of macroscopic tensile stress, the microscopic failure mechanism of particle reinforced metal matrix composites is interface debonding, which is beneficial to the fracture toughness of particle reinforced metal matrix composites. Therefore, this process parameter can be used for preparation, but it needs to be further optimized until If it is close to 1 but not equal to 1, then the process parameters at this time are optimal.

[0051] Example

[0052] This embodiment uses SiC p Reinforced 6092 aluminum matrix composite material 6092Al / SiC p For the implementation of the object, the judgment process includes the following steps:

[0053] 1. The proposed particle volume fraction is 17.5%, the Poisson's ratio is 0.14, and the particle shear modulus μ P is 179.82GPa, and the shear modulus of the metal matrix μ M is 25.56GPa, γ is 0.4884, μ * Calculated to be 7519.2GPa.

[0054] 2. Determine the yield stress σ0 of the metal matrix material to be 280MPa and the critical plastic strain is 0.0.075, and the strength coefficient K of the metal matrix material is 131.7MPa. The calculated damage function intermediate parameter Φ * It is 0.2497.

[0055] 3. Determine the fracture toughness K of the particle ΙC It is 4.6MPam, the particle diameter d is 49.2μm, and the critical particle fracture stress considering the particle size effect is calculated to be 370MPa.

[0056] 4. Critical plastic strain is 0.075, the strength coefficient K of the metal matrix material is 131.7MPa, and the intermediate parameter Φ of the damage function * is 0.2497, the particle volume fraction f is 0.175, and the elastic factor μ of the incompatible plasticity between the metal matrix and the particles is * It is 7519.2GPa, and the maximum particle bearing stress is determined to be 322MPa.

[0057] 5. By comparison Under the condition of macroscopic tensile stress, the microscopic failure mechanism of particle reinforced metal matrix composites is interface debonding, which is beneficial to the fracture toughness of particle reinforced metal matrix composites. This process parameter can be used for preparation, but it needs to be further optimized until Close to 1 but not equal to 1. Continue to adjust the particle volume fraction f to 23%, and then determine the maximum particle bearing stress is 366.8MPa, The optimal process parameters are as follows: particle volume fraction f is 23% and particle diameter d is 49.2 μm. Figure 1 shown.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for predicting failure mechanism of particle reinforced metal matrix composites based on particle size effect, characterized in that: Determine the maximum stress borne by the particles under the condition that the metal matrix composite is subjected to tensile stress , the critical particle fracture stress is determined based on the particle size and fracture toughness of the particles in the metal matrix composite ; when Greater than When the interface debonding of the metal matrix composite material occurs first, then the particle fracture occurs; when Less than When , only interfacial debonding occurs in the metal matrix composite material; if Greater than , then by adjusting the particle volume fraction, adjust ,to Less than ;if Less than , by adjusting the particle volume fraction, adjusting , until and The difference between them is ≤5Mpa; Determine the maximum stress borne by the particle The calculation formula is: in, is the critical plastic strain, It is an elastic factor that is inconsistent with the plasticity of the metal matrix and particles. f is the particle volume fraction, is the intermediate parameter of the damage function, K is the strength coefficient of the metal matrix; Elastic factors of incompatible plasticity between metal matrix and particles The calculation formula is: in, is the shear modulus of the metal matrix, is the shear modulus of the particle, is the Eshelby factor; Eshelby factor of spherical particles The expression is 1-2(4-5 ) / 15(1- ); Damage function intermediate parameters The calculation formula is: in, is the critical plastic strain; is the strength coefficient of the metal matrix, is the yield stress of the metal matrix, f is the particle volume fraction, It is an elastic factor that is inconsistent with the plasticity of the metal matrix and particles.

2. The method for predicting failure mechanism of particle reinforced metal matrix composites based on particle size effect according to claim 1, characterized in that: Critical particle fracture stress The calculation formula is: in, is the fracture toughness of the particle, is the particle diameter.

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