A method for quickly analyzing material anisotropy factor distribution based on EBSD data

Abstract

The application discloses a kind of based on EBSD data fast analysis material anisotropy factor distribution method, S1: the backscattering diffraction pattern of sample area to be analyzed is collected using electron backscattering diffractometer and original diffraction pattern data is extracted and obtained;S2: the original diffraction pattern data is processed based on orientation preset process through preset model, and the distribution and statistical information of anisotropy factor of the area to be analyzed are obtained.The application belongs to the technical field of material structure analysis, and specifically relates to a kind of based on EBSD data fast analysis material anisotropy factor distribution in specific range method.The method fills the blank in the analysis of anisotropy factor based on EBSD data, and is beneficial to the preliminary evaluation of material modulus, damping and magnetostriction and other performances.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material structure analysis, and particularly relates to a method for rapidly analyzing material anisotropy factor distribution based on EBSD data. BACKGROUND

[0002] The change of the modulus and damping value of the crystal structure material is generally related to the anisotropy factor (Gamma) associated with the direction of the external force field or magnetic field to which the material is subjected, and particularly for ferromagnetic alloys, the magnetostriction size and magnetic crystal anisotropy are also closely related to the anisotropy factor of the material. For example, for a cubic structure material, the elastic modulus of any orientation is generally calculated according to the following relationship:

[0003] E -1 =S 11 -2(S 11 -S 12 -1 / 2S 44 )Gamma, (1)

[0004] Where S 11 , S 12 , S 44 are the elastic compliance, and after stress relaxation, the material energy loss intensity can be described as:

[0005]

[0006] Where Ju is the unrelaxed elastic compliance. For a ferromagnetic polycrystal, the magnetostriction can also be represented by the anisotropy factor, that is,

[0007]

[0008] Lambda 111 and Lambda 100 are the magnetostriction coefficients of

[111] and

[100] directions, respectively. Therefore, by analyzing the local and overall statistics of the anisotropy factor, the relevant physical properties of different materials can be evaluated.

[0009] Thanks to the rapid development of electron backscatter diffraction (EBSD) technology, the crystal structure, different direction pole figures and inverse pole figures, texture, geometric strain distribution, etc. can be rapidly analyzed. However, the accurate calculation and statistical analysis of the anisotropy factor cannot be realized at present. SUMMARY

[0010] The application aims to fill the gap of the existing EBSD analysis technology in the analysis of the anisotropy factor distribution, and provides a method for rapidly analyzing the material anisotropy factor distribution based on EBSD data, so as to solve the problem of not easy wide-range analysis and statistical analysis and inaccurate value of the anisotropy factor in the prior art.

[0011] The application achieves the above-mentioned purpose through the following technical solutions.

[0012] A method for quickly analyzing anisotropy factor distribution of a material based on EBSD data, comprising the following steps:

[0013] S1: collecting a backscattering diffraction pattern of a sample area to be analyzed by an electron backscattering diffraction instrument and extracting original diffraction pattern data;

[0014] S2: processing the original diffraction pattern data through a preset model based on an orientation preset process to obtain distribution and statistical information of anisotropy factors of the area to be analyzed.

[0015] Further improvement lies in that the sample is mainly a single-phase or multi-phase structure metal sample.

[0016] Further improvement lies in that the original diffraction pattern data in S1 is data point coordinates (X, Y) and Euler indexes The Euler indexes (φ1, Φ, φ2) data in the original diffraction pattern data of the area to be analyzed are converted into Miller index data, starting from the first data point and ending at the last data point of the area to be analyzed.

[0017] Further improvement lies in that, if a specific area or phase needs to be analyzed, the original diffraction pattern data in S1 is data point coordinates (X, Y) and Euler indexes

[0018] Further improvement lies in that the processing of the original diffraction pattern data through a preset model based on an orientation preset process in S2 to obtain distribution and statistical information of anisotropy factors of the area to be analyzed comprises the following steps:

[0019] S201: reading original diffraction pattern data and forming a data point scanning area based on all the original diffraction pattern data;

[0020] S202: performing a calculation process of data points of the scanning area, starting from the first data point and ending at the last data point, and converting Euler index data of the original diffraction pattern of the scanning area into Miller index data based on a G matrix;

[0021] S203: extracting all the Miller index data in the scanning area and setting an analysis orientation and anisotropy reference axes;

[0022] S204: calculating cosine values of all positions in the scanning area with respect to three reference axes directions, i.e., cosα, cosβ and cosγ, according to the orientation of the Miller index data and the reference axes, and calculating anisotropy factors according to the formula Γ = cos 2alpha*cos 2 beta+cos 2 beta*cos 2 gamma+cos 2 gamma*cos 2 alpha, calculate the one-dimensional anisotropy factor of all points in the scanning area; wherein the Euler index of each point in the region to be analyzed Phi, Data is combined into a vector d, and the cosine value between the vector d and the anisotropy reference axis is calculated respectively.

[0023] S205: the obtained one-dimensional anisotropy factor data is converted into three-dimensional matrix data;

[0024] S206: after the coordinates of the three-dimensional matrix data are segmented, an anisotropy factor distribution map is formed, the blank treatment is carried out after the unrecognition area is scanned by EBSD, and the average value of the segmented anisotropy factor distribution map is formed to form the anisotropy factor distribution data.

[0025] Further improvement lies in that the G matrix and Miller index relationship are:

[0026]

[0027] Further improvement lies in that the analysis orientation in S203 is along the x-axis direction of the sample coordinate system SCS, that is, [u vw], or along the z direction of SCS; the anisotropy reference axis is

[100] -

[010] -

[001] , but in special cases, the orientation can be modified as required, for example,

[100] -

[011] -[01-1].

[0028] Further improvement lies in that it further comprises S3, analyzing material related characteristic quantities based on the anisotropy factor distribution and statistical information data obtained in S2, the characteristic quantities including modulus, damping, magnetostriction, etc.

[0029] The beneficial effects of the present application are as follows: based on the prior art, by extracting EBSD original coordinates and orientation data, and carrying out calculation and setting processing on the data, the accurate anisotropy factor distribution and statistical information of the sample in the EBSD scanning range can be obtained, and the processing process is realized based on Matlab. Through the result, the material micro area anisotropy factor can be analyzed, and the overall anisotropy factor can also be statistically analyzed, so as to facilitate the measurement of the modulus, damping, magnetostriction and other macroscopic information of the material. The following advantages are summarized:

[0030] ① accurate anisotropy factor can be obtained;

[0031] ②Can quickly obtain the distribution of anisotropy factor in a wide range and the corresponding statistical information, filling the current gap of EBSD analysis in this aspect;

[0032] ③The method can be used to evaluate magnetostriction, anisotropy damping, modulus size and the like of materials. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is based on the anisotropy factor distribution (a) and the corresponding statistical information (b) of the FeGa single crystal micro area in Example 1 of the application, and the anisotropy factor distribution (c) and the corresponding statistical information (d) of the FeGa bicrystal micro area;

[0034] Figure 2 is based on the anisotropy factor distribution of the BCC phase (a) and the FCC phase (b) of the complex phase high-strength steel in Example 2 of the application;

[0035] Figure 3 is based on the anisotropy factor distribution (a) and the corresponding statistical information (b) of a BCC high-entropy alloy in Example 3 of the application;

[0036] Figure 4 is based on the anisotropy factor distribution (a) and the corresponding statistical information (b) of a pure copper sample in Example 4 of the application when the reference axis is

[100] -

[011] -[01-1]. DETAILED DESCRIPTION

[0037] It is necessary to point out here that the following detailed description is only used to further illustrate the application, and cannot be understood as limiting the protection scope of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content.

[0038] The application achieves the above-mentioned purpose by the following technical solutions:

[0039] A method for quickly analyzing the anisotropy factor distribution of a material based on EBSD data, comprising the following steps:

[0040] S1: Collecting the backscattering diffraction pattern of the sample area to be analyzed by using an electron backscattering diffractometer and obtaining the original diffraction pattern data:

[0041] The sample is mainly a single-phase or multi-phase metal sample.

[0042] The original diffraction pattern data in S1 is the data point coordinates (X, Y) and Euler index The Euler index (φ1, Φ, φ2) data in the original diffraction pattern data of the region to be analyzed is converted into Miller index data, starting from the first data point and ending with the last data point of the region to be analyzed.

[0043] If a specific region or phase needs to be analyzed, the original diffraction pattern data in S1 is the data point coordinates (X, Y) and Euler index

[0044] S2: The original diffraction pattern data is processed by a preset model based on orientation presetting process to obtain the distribution and statistical information of the anisotropy factor of the region to be analyzed, including the following steps:

[0045] S201: Read the original diffraction pattern data and form a data point scanning region based on all original diffraction pattern data;

[0046] S202: Perform a calculation process for the data points of the scanning region, starting from the first data point and ending with the last data point, and convert the Euler index data of the original diffraction pattern of the scanning region into Miller index data based on the G matrix;

[0047] S203: Extract all Miller index data in the scanning region and set the analysis orientation and anisotropy reference axis;

[0048] S204: According to the orientation of the Miller index data and the reference axis, calculate the cosine values of all positions in the scanning region with respect to the three reference axes, respectively cosα, cosβ, and cosγ, and according to the anisotropy factor formula Γ = cos 2 α*cos 2 β+cos 2 β*cos 2 γ+cos 2 γ*cos 2 α, calculate the one-dimensional anisotropy factor of all positions in the scanning region; wherein the Euler index Φ、 data of each point in the region to be analyzed is combined into a vector d, and the cosine values between the vector d and the anisotropy reference axis are calculated respectively.

[0049] S205: Convert the obtained one-dimensional anisotropy factor data into three-dimensional matrix data;

[0050] S206: Form an anisotropy factor distribution map after dividing the coordinates of the three-dimensional matrix data, perform blank processing on the unrecognition region after scanning by EBSD, and form an anisotropy factor distribution data according to the average value of the divided anisotropy factor distribution map.

[0051] Wherein, the relationship between the G matrix and the Miller index is:

[0052]

[0053] Wherein, the analysis orientation in S203 is along the x-axis direction of the sample coordinate system SCS, that is, [u v w], or along the z direction of SCS; the anisotropy reference axis is

[100] -

[010] -

[001] , but in special cases, the orientation can also be modified as required, for example,

[100] -

[011] -[01-1].

[0054] In order to fully illustrate the present application, the following specific embodiments are provided:

[0055] Embodiment 1

[0056] The embodiment provides a method for rapidly analyzing material anisotropy factor distribution based on EBSD data, specifically FeGa single crystal and polycrystal anisotropy factor detection and damping, magnetostriction performance evaluation, comprising the following steps:

[0057] Step one: collect the diffraction pattern of the specific analysis area of the FeGa single crystal and polycrystal sample by an electron backscatter diffraction instrument;

[0058] Step two: extract the original diffraction pattern data from the EBSD analysis software and export the data, convert the Euler index (φ1, Φ, φ2) data in the original diffraction pattern data of the area to be analyzed into Miller index data, starting from the first data point to the last data point of the area to be analyzed;

[0059] Step three: set the analysis orientation (force or magnetic field direction) along the x-axis and the anisotropy reference axis as

[100] -

[010] -

[001] ;

[0060] Step four: process the EBSD original data, the analysis orientation and the anisotropy reference axis obtained in step three through a preset model based on the orientation preset process, to obtain the distribution of the anisotropy factor of the entire area, as well as the anisotropy factor distribution density map, the average value, etc., as shown in Figure 1 It can be seen that the single crystal anisotropy factor distribution is very concentrated, while the double crystal anisotropy factor shows a bimodal distribution, and the average anisotropy factor of the single crystal is much higher than that of the double crystal. Combined with formulas (2) and (3), it can be known that the damping and magnetostriction of the single crystal under the action of the parallel x-axis normal stress or magnetic field are smaller than those of the double crystal.

[0061] Embodiment 2

[0062] The embodiment provides a method for rapidly analyzing material anisotropy factor distribution based on EBSD data, specifically anisotropy factor analysis of different phase structures of complex phase high-strength steel:

[0063] Step one: Collecting the backscattered diffraction pattern of the specific analysis area of the multi-phase high-strength steel sample by an electron backscattered diffraction instrument;

[0064] Step two: Establishing a phase subset from the EBSD analysis software and extracting the original diffraction pattern data of the BCC and FCC structures respectively;

[0065] Step three: Setting the analysis orientation along the z-axis and the anisotropy reference axis as

[100] -

[010] -

[001] ;

[0066] Step four: Processing the EBSD original data and the analysis orientation and anisotropy reference axis obtained in step three based on the orientation preset process through a preset model to obtain the distribution of the anisotropy factor of different phase structures, as shown in Figure 2 It can be seen that the average values of the BCC and FCC anisotropy factors are comparable.

[0067] Example 3

[0068] The present embodiment provides a method for rapidly analyzing the anisotropy factor distribution of a material based on EBSD data, specifically, an anisotropy factor analysis and modulus evaluation of a BCC high-entropy alloy along the x-axis direction under normal stress:

[0069] Step one: Collecting the diffraction pattern of the specific analysis area of the high-entropy alloy sample by an electron backscattered diffraction instrument;

[0070] Step two: Extracting the original diffraction pattern data of the structure from the EBSD analysis software

[0071] Step three: Setting the analysis orientation along the x-axis and the anisotropy reference axis as

[100] -

[010] -

[001] ;

[0072] Step four: Processing the EBSD original data and the analysis orientation and anisotropy reference axis obtained in step three based on the orientation preset process through a preset model to obtain the distribution and statistical information of the anisotropy factor of the sample, as shown in Figure 3 It can be seen from formula (1) that the modulus of the selected polycrystalline high-entropy alloy is moderate compared to the

[100] single crystal and the

[111] single crystal.

[0073] Example 4

[0074] The present embodiment provides a method for rapidly analyzing the anisotropy factor distribution of a material based on EBSD data, specifically, an anisotropy factor analysis of a pure copper sample when the reference axis is

[100] -

[011] -[01-1]:

[0075] Step one: Collecting the diffraction pattern of the specific analysis area of the pure copper sample by an electron backscattered diffraction instrument;

[0076] Step two: extract the original diffraction pattern data of the structure from the EBSD analysis software;

[0077] Step three: set the analysis orientation along the x-axis and the anisotropy reference axis as

[100] -

[011] -[01-1];

[0078] Step four: process the EBSD original data and the analysis orientation and anisotropy reference axis obtained in step three through the preset model based on the orientation preset process to obtain the distribution and statistical information of the anisotropy factor of the sample, and the result is shown in Figure 4

[0079] Compared with the prior art, the method for quickly analyzing the anisotropy factor distribution of a material based on EBSD data can analyze the anisotropy factor of a micro area of the material, and can also statistically analyze the anisotropy factor of the whole material, which is beneficial to measure the modulus, damping, magnetostriction and other parameters closely related to the anisotropy factor of the material.

[0080] The above-described embodiments only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application.​

Claims

1. A method for rapid analysis of the distribution of anisotropy factors of a material based on EBSD data, characterized in that, The method comprises the following steps: S1: collecting a backscattering diffraction pattern of a region to be analyzed of a sample by using an electron backscattering diffraction instrument and extracting original diffraction pattern data, the original diffraction pattern data being data point coordinates (X, Y) and Euler indexes (φ1, Φ, φ2) corresponding to a phase subset or a region subset; S2: processing the original diffraction pattern data through a preset model based on an orientation preset process to obtain distribution and statistical information of anisotropy factors of the region to be analyzed; specifically: S201: reading the original diffraction pattern data and forming a data point scanning region based on all the original diffraction pattern data; S202: performing a calculation process of data points of the scanning region, starting from a first data point and ending at a last data point, and converting Euler index data of the original diffraction pattern of the scanning region into Miller index data based on a G matrix; S203: extracting all the Miller index data in the scanning region and setting an analysis orientation and an anisotropy reference axis; S204: According to the azimuth of the Miller index data and the reference axis, the cosine values of all positions in the scanning region in the directions of the three reference axes are calculated, respectively cos a, cos β, and cos γ, and the one-dimensional anisotropy factor of all positions in the scanning region is calculated according to the anisotropy factor formula Γ = cos 2 a*cos 2 β + cos 2 β*cos 2 γ + cos 2 γ*cos 2 a. S205: converting the obtained one-dimensional anisotropy factor data into three-dimensional matrix data; S206: forming an anisotropy factor distribution map after segmenting coordinates of the three-dimensional matrix data, performing blank processing on unrecognition regions after scanning by EBSD, and forming anisotropy factor distribution data according to an average value after segmentation of the anisotropy factor distribution map.

2. The method for quickly analyzing the distribution of anisotropy factor of a material based on EBSD data according to claim 1, characterized in that, The sample is a single-phase or multi-phase structure metal sample.

3. The method for quickly analyzing the distribution of anisotropy factor of a material based on EBSD data according to claim 1, characterized in that, The G matrix and the Miller index relationship are: 。 4. The method for quickly analyzing the distribution of anisotropy factor of a material based on EBSD data according to claim 1, characterized in that, The analysis orientation in S203 is along an x-axis direction of a sample coordinate system SCS, namely [u v w], or along a z direction of the SCS.

5. The method for quickly analyzing the distribution of anisotropy factor of a material based on EBSD data according to claim 1, characterized in that, The anisotropy reference axis in S203 is [100]-[010]-[001] or [100]-[011]-[01-1].

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