A method for rapidly screening high-forming amorphous alloy components and locating crystallization areas

Abstract

The present invention provides a method for rapidly screening amorphous alloy components with high forming ability and locating crystallization areas, and relates to the technical field of amorphous alloy materials. Specifically, by characterizing the free surface morphology of the alloy, the amorphous alloy components can be rapidly screened; by measuring the height profile of the alloy surface and performing a second-order differential transformation, the tiny grains on the surface can be observed with higher precision. By statistically analyzing the proportion of the grain interval, the relative content of amorphous can be obtained. Optionally, the dark field phase of an optical microscope can also realize quantitative analysis of the relative content of amorphous on the sample surface. In addition, by combining the free surface morphology characterization and the second-order differential curve of the height profile curve for analysis, the crystallization area can be rapidly located. Compared with the traditional amorphous structure characterization method, the present invention can rapidly screen the amorphous alloy component interval, quantitatively calculate the relative content of crystals and the relative size of grains, and locate the crystallization area, with high characterization efficiency, high accuracy, and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of amorphous alloy materials, and in particular relates to a method for rapidly screening amorphous alloy components with high forming ability and locating crystallization areas. Background Art

[0002] Amorphous alloys (or metallic glasses) are a general term for metal alloys whose atomic arrangements have long-range disorder and short-range order structural characteristics. Compared with traditional crystalline alloys, amorphous alloys have better physical and chemical properties, such as ultra-high strength, high hardness, excellent wear resistance and corrosion resistance, due to the lack of periodic symmetry, anisotropy, dislocations and grain boundaries in their structures. Therefore, such materials have important application prospects in many cutting-edge fields such as aerospace, military industry, micro-electromechanical and electronic chemical engineering. However, the size limitation of amorphous alloys due to their amorphous forming ability seriously restricts their further application. Reasonable composition design and development can significantly improve the forming ability of amorphous alloys, but the huge element candidate library and multi-component composition design have brought great difficulties to the development of new systems of amorphous alloys.

[0003] The development of amorphous alloys generally includes three stages: composition design, sample preparation, and structural characterization. At present, the traditional structural characterization methods are mainly X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). Among them, TEM requires a complex sample preparation process and is expensive. DSC needs to reduce the sample to less than tens of milligrams and the characterization time is long. XRD, as the most widely used characterization method, takes at least more than ten minutes. Faced with the huge library of amorphous alloys to be selected, the above three methods are inefficient and seriously limit the development of new amorphous alloy systems.

[0004] Taking the ternary alloy system as an example, there are more than 4,700 designed components, but the actual amorphous formation region may only be hundreds or even dozens. Therefore, an efficient characterization method is needed to quickly screen and obtain the amorphous formation composition range. Summary of the invention

[0005] The object of the present invention is to provide a method for rapidly screening amorphous alloy components with high forming ability and locating crystallization areas. By characterizing the free surface morphology of the alloy, the amorphous alloy components can be quickly identified; by measuring the height profile of the alloy surface and performing a second-order differential transformation, the tiny grains on the surface can be observed with higher precision. Furthermore, by statistically analyzing the proportion of the grain interval, the relative content of amorphous can be obtained. Alternatively, the dark field phase of a statistical optical microscope can also realize quantitative analysis of the relative content of amorphous on the sample surface. In addition, by combining the surface morphology characterization with the second-order differential curve of the height profile curve, the crystallization area can be quickly located.

[0006] The present invention can qualitatively and quantitatively characterize the amorphous phase content and crystallized region of the alloy by observing the morphology of the free surface. Compared with the traditional amorphous structure characterization method, the present invention can quickly identify the amorphous component range, with high characterization efficiency and low cost.

[0007] To achieve the above object, the present invention provides a method for rapidly screening high-forming ability amorphous alloy components and locating crystallization regions, which specifically comprises the following steps:

[0008] Preparation of alloy samples: obtaining alloy free surface;

[0009] Qualitative identification of amorphous components: Place the free surface of the alloy under a microscope with a differential interference imaging module to observe the height difference of its differential interference microscopic morphology;

[0010] Quantitative calculation of relative crystal content and relative grain size: including second-order differential statistics of profile height or dark field phase observation method.

[0011] In a preferred embodiment, it also includes locating the crystallized area: using the second-order differential statistical method of profile height to analyze the position distribution of the fluctuation segment in the second-order differential curve of the free surface height profile and combining it with the differential interference microscopic morphology image of its surface, the crystallized area can be quickly located.

[0012] In a preferred embodiment, in the step of preparing the alloy sample, the surface roughness of the free surface of the alloy is ≤100 μm.

[0013] In a preferred embodiment, in the step of qualitatively identifying amorphous components, a microscope with a differential interference imaging module is used, and the height difference of the observed local morphology comes from the different degrees of local crystallization of the sample: if the height difference of the morphology is manifested as no local height fluctuation, and the morphology is smooth and flowing, then it is an amorphous structure; if the height difference of the morphology is manifested as obvious local height fluctuation and the morphology is completely rough, then it is a crystalline structure; if the height difference of the morphology is manifested as local fluctuation, shrinkage, or particles precipitated under a smooth substrate, then it is a semi-amorphous structure.

[0014] In a preferred embodiment, the second-order differential statistical method of profile height includes the following steps: measuring the profile height of the free surface of the alloy, performing second-order differential calculation on the measured profile height curve to form a second-order differential curve, and performing statistics on the mutation range of the second-order differential curve.

[0015] In a preferred embodiment, in the profile height second-order differential statistics method, the profile height measurement of the alloy free surface includes line profile height and / or surface profile height, and the height profile measurement resolution can be up to 20 nm.

[0016] In a preferred embodiment, in the second-order differential statistical method of profile height, the second-order differential calculation formula is: H″=Hi +1 +Hi -1 +2Hi (i = 2, 3, 4, 5 ... n), where H "is the second-order differential value of the height profile curve along the baseline length, Hi +1 、Hi -1 , Hi are the corresponding height values ​​on the height profile curve, and n is the total number of points collected by the height profile curve.

[0017] In a preferred embodiment, in the second-order differential statistics method of contour height, the mutation range of the second-order differential curve is ±0.1 of the vertical axis, the statistical mutation range corresponds to the horizontal coordinate length of the fluctuation segment, and its ratio to the total length of the baseline is obtained, and the result is the relative content of the crystalline phase in the direction of the baseline.

[0018] In a preferred embodiment, in the step of quantitatively calculating the relative crystal content and the relative grain size, the dark field phase observation method includes the following steps: placing the free surface of the alloy under the dark field phase of an optical microscope for observation, and counting the proportion of the bright area to the total area of ​​the field of view.

[0019] In a preferred embodiment, the method is applicable to all amorphous alloy systems for rapid identification of amorphous components, calculation of the relative content of crystals and / or amorphous phases, and / or location of crystallization regions, and comparison of the amorphous forming abilities of different components, thereby screening amorphous alloy components with high forming ability, without the need for complicated sample preparation, with short characterization time and high accuracy.

[0020] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0021] The present invention creatively utilizes the macroscopic uniformity of the amorphous structure, that is, the free surface of the amorphous structure has a smooth morphological feature; while the free surface roughness of the crystalline structure is relatively large due to the different preferred orientations of the grains and the volume shrinkage that occurs during crystallization, presenting an undulating morphological feature; the effect of rapid identification can be achieved through feature comparison. The operation steps are simple, the method is universal to all amorphous alloy systems, the sample does not require complex pretreatment and tedious sample preparation, the characterization time is short, and the accuracy is high. It can effectively reduce the characterization cost and has low requirements for equipment and operators.

[0022] Furthermore, under the same preparation parameters, that is, ensuring the same cooling rate, the amorphous content of the sample can be quantitatively evaluated to determine the amorphous ability of different components, thereby accurately and efficiently screening out alloy components with strong glass-forming ability.

[0023] The technical solution of the present invention can also quickly determine the location of the crystallization area in the sample and perform statistics on the grain size caused by crystallization. In terms of judging the crystallization of the sample, compared with the traditional characterization method, the present invention has a larger spatial resolution and can perform free characterization within the sample space. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] These and / or other aspects and advantages of the present invention will become more clear and easier to understand from the following detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0025] Figure 1 Ni of Example 1 of the present invention 62 Nb 38 The free surface differential interference microscopy morphology of the amorphous structure sample (left), the selected area electron diffraction pattern of the corresponding smooth area by transmission electron microscopy (middle) and its X-ray diffraction pattern (right);

[0026] Figure 2 Ni of Example 1 of the present invention 54 Nb 46 Differential interference microscopy of the free surface of a crystalline structure sample (left), selected area electron diffraction pattern of the transmission electron microscope corresponding to the local height fluctuation (middle) and X-ray diffraction pattern (right);

[0027] Figure 3 It is an example of the free surface height profile curve and its second-order differential curve of the sample in the present invention;

[0028] Figure 4 Ni of Example 1 of the present invention x Nb 100-x Differential interference microscopy topography of the sample free surface;

[0029] Figure 5 Ni of Example 1 of the present invention x Nb 100-x The second-order differential curve of the height profile curve of the sample free surface;

[0030] Figure 6 Ni of Example 1 of the present invention x Nb 100-x Dark field topography of the sample free surface;

[0031] Figure 7 Co of Example 2 of the present invention 55 Ta 10 B 35 and Co 53 Ta 8 B 39 Differential interference microscopy topography of the strip sample;

[0032] Figure 8 Co of Example 2 of the present invention 55 Ta 10 B 35 and Co 53 Ta 8 B 39 The second-order differential curve of the height profile curve of the strip sample;

[0033] Fig. 9 is the Cu of Example 3 of the present invention 50 Zr 50 Differential interference microscopy topography of the sample free surface;

[0034] Fig.10 is the Cu of Example 3 of the present invention 50 Zr 50 Contour curve of the surface height profile of the sample free surface;

[0035] Fig.11 Ni of Example 4 of the present invention 60 Ta 40 Differential interference microscopy topography of the sample free surface. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods, but it should be understood that the protection scope of the present invention is not limited to the specific implementation methods.

[0037] The present invention provides a method for rapidly screening high-forming amorphous alloy components and locating crystallization areas, thereby solving the problems in the prior art of complex and cumbersome amorphous alloy characterization process and a huge candidate library of amorphous alloy elements, which leads to low efficiency and long time in the composition design and screening of amorphous alloys.

[0038] The technical solution in the embodiment of the present invention is to solve the above problems, and the overall idea is as follows:

[0039] A method for rapidly screening high-forming-ability amorphous alloy components and locating crystallization regions comprises the following steps:

[0040] Preparation of alloy samples: obtaining alloy free surface;

[0041] Qualitative identification of amorphous components: Place the free surface of the alloy under a microscope with a differential interference imaging module to observe the height difference of its differential interference microscopic morphology;

[0042] Quantitative calculation of relative crystal content and relative grain size: including second-order differential statistics of profile height or dark field phase observation method.

[0043] In a preferred embodiment, it also includes locating the crystallized area: using the second-order differential statistical method of profile height to analyze the position distribution of the fluctuation segment in the second-order differential curve of the free surface height profile and combining it with the differential interference microscopic morphology image of its surface, the crystallized area can be quickly located.

[0044] It should be noted that in the present method, there is no order in which the steps of qualitatively identifying the amorphous component and quantitatively calculating the relative content of the (amorphous) crystal can be performed, and qualitative identification can be performed first, or quantitative calculation can be performed first. If there is no need to locate the crystallized area, only the steps of qualitatively identifying the amorphous component or quantitatively calculating the relative content of the (amorphous) crystal can be performed, and the above single steps are all within the scope of protection of the present invention.

[0045] In a preferred embodiment, in the step of preparing the alloy sample, the alloy free surface can be prepared by any method known to those skilled in the art, and the preparation method of the alloy sample will not affect the purpose of the present invention. More preferably, the method for obtaining the alloy free surface includes: a traditional rapid solidification method, a laser scanning method, and a coating deposition method.

[0046] 1) Preparation of alloy thin strips by traditional rapid solidification method: According to the nominal composition of the alloy, the single elements weighed in proportion are mixed evenly to obtain the smelting raw materials. Then the smelting raw materials are placed in a vacuum induction melting furnace or a vacuum arc furnace under the protection of a high-purity argon atmosphere to obtain a master alloy ingot.

[0047] Furthermore, the master alloy ingot prepared as above is crushed and placed in a quartz tube, and after being evacuated and filled with argon atmosphere, a rapid solidification device is used to prepare an alloy strip.

[0048] 2) Preparation of laser samples by laser scanning: This preparation method includes two types of sample preparation. The first is to mechanically process the master alloy ingot prepared by the above method to obtain a plane suitable for laser scanning, and then perform laser rapid scanning under argon atmosphere protection after vacuum to obtain a laser melt-quenched layer;

[0049] The second method is laser additive manufacturing, which involves using a laser to scan alloy powder or mixed single-element powder under the protection of an argon atmosphere after vacuuming to obtain a laser cladding layer.

[0050] 3) Preparation of thin film samples by coating deposition method: Alloy thin film samples are prepared by coating deposition method.

[0051] The free surface of the alloy obtained by the above-mentioned preparation method can be structurally characterized using the rapid screening method of amorphous alloys provided by the present invention. It should be noted that, in addition to the preparation method mentioned above, the free surface morphology obtained by other preparation methods can be screened for amorphous alloy components using the scheme of the present invention, which cannot be exhaustively listed here, and therefore cannot be specifically limited.

[0052] In a preferred embodiment, in the step of preparing the alloy sample, the surface roughness of the free surface of the alloy is ≤100 μm; preferably, the prepared alloy can be cleaned to remove impurities so as not to affect the characterization results. The reason for limiting the surface roughness of the free surface of the alloy is that compared with the crystal structure, the amorphous alloy itself has a very smooth free solidification surface, which is easy to implement the characterization analysis of the present invention; moreover, the roughness ≤100 μm can reduce the error generated during the characterization and improve the accuracy.

[0053] In a preferred embodiment, in the step of qualitatively identifying amorphous components, the microscope with a differential interference imaging module can be any microscope with interference imaging function known to those skilled in the art, and preferably, a differential interference microscope can be used.

[0054] In a preferred embodiment, in the step of qualitatively identifying the amorphous component, when a differential interference microscope is used, the prism angle can also be adjusted according to the actual height of the sample to more clearly display the local morphology of the sample.

[0055] In a preferred embodiment, in the step of qualitatively identifying the amorphous component, a microscope with a differential interference imaging module is used, and the height difference of the local morphology observed is derived from the difference in the local crystallization degree of the sample. Specifically: Figure 1 As shown on the left, the free surface of the amorphous structure is completely smooth, while the crystal structure has a granular and rough morphology under differential interference microscopy due to the shrinkage of local volume and different preferred orientations. Figure 2 The above discovery is the result of a large number of experimental observations and transmission electron microscopy ( Figure 1 and Figure 2 middle figure) and X-ray diffractometer ( Figure 1 and Figure 2 Based on the conclusion obtained after verification (right figure), the inventors designed a technical solution for quickly identifying amorphous components.

[0056] In a preferred embodiment, in the step of qualitatively identifying amorphous components, if the height difference of the morphology is manifested as no local height fluctuation and the morphology is smooth and flowing, it is an amorphous structure; if the height difference of the morphology is manifested as obvious local height fluctuation and the morphology is completely rough, it is a crystalline structure; if the height difference of the morphology is manifested as local fluctuation, contraction or particles precipitated under a smooth substrate, it is a semi-amorphous structure. The above identification scheme has an accuracy rate of nearly 100% after verification by an X-ray diffractometer and a transmission electron microscope, and can effectively and quickly identify amorphous components.

[0057] In a preferred embodiment, the second-order differential statistical method of profile height includes the following steps: measuring the profile height of the free surface of the alloy, performing second-order differential calculation on the measured profile height curve to form a second-order differential curve, and performing statistics on the mutation range of the second-order differential curve.

[0058] In a preferred embodiment, in the second-order differential statistics method of profile height, the device for measuring the profile height of the free surface of the alloy can be any device known to those skilled in the art, as long as it can measure the profile height. Preferably, a confocal microscope or a white light interferometer can be used.

[0059] In a preferred embodiment, in the second-order differential statistics method for profile height, the height profile measurement of the alloy free surface includes contact measurement or non-contact measurement, neither of which will affect the realization of the technical effect of the present invention.

[0060] In a preferred embodiment, in the profile height second-order differential statistics method, the profile height measurement of the alloy free surface includes line profile height and / or surface profile height, and the height profile measurement resolution can be up to 20 nm.

[0061] In a preferred embodiment, in the second-order differential statistical method of profile height, the second-order differential calculation formula is: H″=H i+1 +H i-1 +2H i (i=2,3,4,5……n), where H″ is the second-order differential value of the height profile curve along the baseline length, H i+1 , H i-1 , H i are the corresponding height values ​​on the height profile curve, and n is the total number of points collected by the height profile curve.

[0062] In a preferred embodiment, in the second-order differential statistics method of contour height, the mutation range of the second-order differential curve is ±0.1 of the vertical axis, the statistical mutation range corresponds to the horizontal coordinate length of the fluctuation segment, and its ratio to the total length of the baseline is obtained, and the result is the relative content of the crystalline phase in the direction of the baseline.

[0063] The present invention has found in a large number of actual observations that the local volume shrinkage caused by crystallization and the difference in preferred orientation of grains will cause local mutations in the profile height curve of the free surface of the sample. Therefore, by statistically analyzing the local mutation area on the height profile curve of the free surface of the sample, the relative content of the crystalline phase can be obtained. Furthermore, by performing a second-order differential on the height profile curve, the difference in local height changes caused by tiny grains can be amplified. By performing statistics on the height mutation area of ​​the second-order differential curve of the height profile curve, a more accurate quantitative analysis of the crystallized area can be achieved.

[0064] For example: Figure 3 As shown in Figure 2, when the sample is an amorphous structure, the profile height curve is relatively smooth, and its second-order differential curve is a slightly fluctuating straight line ( Figure 3 Left). Alternatively, this method can also be used to measure the height profile curve of the sample free surface to screen the amorphous alloy composition. As the grains precipitate, the height profile fluctuates locally, and the second-order differential curve fluctuates greatly ( Figure 3 Right). Comparing the height profile curve and the corresponding second-order differential curve fluctuation segment, the horizontal coordinates are completely consistent. Therefore, the relative crystal content can be obtained by calculating the ratio of the horizontal coordinates of the fluctuation segment. Furthermore, the second-order differential curve can amplify the height fluctuation caused by crystallization and improve the accuracy of statistics. Furthermore, since the fluctuation amplitude of the second-order differential curve is well consistent with the size of the grain, the relative size of different grains can be compared by comparing the curves of grains of different sizes.

[0065] In a preferred embodiment, in the step of quantitatively calculating the relative crystal content and the relative grain size, the dark field phase observation method includes the following steps: placing the free surface of the alloy under the dark field phase of an optical microscope for observation, and counting the proportion of the bright area to the total area of ​​the field of view.

[0066] The inventors observed that the local height difference caused by crystallization will cause bright areas to appear in the dark field phase, and the relative content of amorphous phases can be obtained by counting the proportion of the bright area to the total area of ​​the field of view. Preferably, the dark field image is thresholded using ImageJ software to divide the dark area of ​​the amorphous area and the bright area of ​​the crystallized area, and then the software is used to count the proportion of the bright area to obtain the relative content of the crystalline phase in the dark field morphology.

[0067] In a preferred embodiment, the method is applicable to all amorphous alloy systems for rapid identification of amorphous components, calculation of the relative content of crystals and / or amorphous phases, and / or location of crystallization regions, and comparison of the amorphous forming abilities of different components, thereby screening amorphous alloy components with high forming ability, without the need for complicated sample preparation, with short characterization time and high accuracy.

[0068] The technical solution of the present invention is described in detail below through specific implementation modes:

[0069] Unless otherwise specified, the technical means used in the present invention are conventional means well known to those skilled in the art, and the various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0070] Example 1

[0071] Based on a rapid screening method for amorphous alloys based on free surface morphology, this embodiment uses laser melting and quenching technology to prepare Ni x Nb 100-x The glass-forming ability of the samples was evaluated, and the process included:

[0072] Step 1: Preparation of alloy samples

[0073] Weigh each element according to the nominal composition, and the purity of each element shall not be less than 99.0%. Mix the single elements weighed in proportion and put them into the vacuum arc melting furnace. Draw the vacuum to 8×10 -3 Pa, and then 0.05MPa of high-purity argon with a purity of 99.9% is introduced as a protective gas, the single element is smelted for 2 minutes, and the smelting is repeated 4 times to obtain the mother alloy.

[0074] The master alloy was machined to obtain a plane suitable for laser scanning, and the oxide layer was polished off, and then ultrasonically cleaned with alcohol for 3 minutes. The cleaned sample was glued to the copper mold with silicone grease and placed in the laser processing chamber, and the vacuum was drawn to 2×10 -1 Pa and introduce high-purity argon gas, perform laser melting and quenching treatment in the argon atmosphere protective gas, and obtain a laser melting and quenching surface layer.

[0075] Step 2: Qualitative characterization of amorphous structure using differential interference microscopy

[0076] The alloy sample prepared in step 1 was placed under a differential interference microscope to characterize the morphology of the free surface. Figure 4 As shown. Under differential interference microscopy, the free surface of the amorphous structure is completely smooth, while the crystal structure has a granular and rough morphology due to the shrinkage of the local volume and the difference in preferred orientation. Therefore, it can be easily and quickly compared to get Ni 62 Nb 38 The surface of the sample of the component has a completely amorphous structure, while the other samples have different degrees of crystallization.

[0077] Step 3: Quantitative analysis of amorphous phase in samples

[0078] The height profile curve of the free surface of the sample prepared in step 1 was measured using a laser confocal microscope, and the second-order differential of the curve was taken. The results are as follows: Figure 5 As shown. The free surface of the amorphous structure has a relatively gentle second-order differential curve. With the precipitation of grains, the second-order differential curve fluctuates in a large range, and the proportion of the fluctuation section increases with the increase of the degree of crystallization. The amorphous forming ability of different compositions (such as Figure 5 (shown in the lower right figure).

[0079] Alternatively, a qualitative assessment of the amorphous phase content can also be achieved using dark field phase, with the results shown in Figure 2. Figure 6 As shown in the figure. The smooth free surface of the amorphous structure makes the oblique incident light in the dark field reflect out of the field of view, and the field of view appears as a dark area; the local height caused by crystallization makes part of the incident light enter the field of view and appear as a bright area. The dark field phase results show that Ni 62 Nb 38 The component has the highest glass-forming ability.

[0080] Step 4: Determination of the crystallization area and relative grain size in the sample

[0081] Combining the differential interference microscopy morphology of the sample free surface and the second-order differential curve analysis of the height profile curve, the grain precipitation area first appears in the laser scanning overlap area, because this area has experienced more thermal cycles during the laser scanning process, and it is more likely to nucleate and grow crystals. And comparing the fluctuation amplitude of the second-order differential curve of the sample free surface height profile curve, it is concluded that Ni 60 Nb4 0 To You 54 Nb 46 The grain size increases gradually.

[0082] Example 2

[0083] Based on a rapid screening method for amorphous alloys based on free surface morphology, this example is a rapid solidification technology prepared Co 55 Ta 10 B 35 and Co 53 Ta 8 B 39 The amorphous phase of the strip sample is evaluated by the following process:

[0084] Step 1: Preparation of alloy samples

[0085] Weigh each element according to the nominal composition, and the purity of each element shall not be less than 99.0%. Mix the single elements weighed in proportion and put them into a vacuum high-frequency melting furnace first, and draw the vacuum to 1×10 -2Pa, and then 0.05MPa of high-purity argon gas with a purity of 99.9% is introduced as a protective gas, and the single element is smelted for 3 minutes. The smelting is repeated 4 times to obtain a prefabricated alloy.

[0086] The prefabricated alloy was placed in a copper mold and then placed in a vacuum arc melting furnace. The vacuum was drawn to 8×10 -3 Pa, and then 0.05MPa of high-purity argon with a purity of 99.9% is introduced as a protective gas, the single element is smelted for 2 minutes, and the smelting is repeated 5 times to obtain the mother alloy.

[0087] The master alloy was crushed and placed in a quartz tube, which was then placed in a rapid solidification device and vacuumed to 5×10 -2 Pa, and then 0.05MPa of high-purity argon with a purity of 99.9% is introduced as a protective gas. After heating to melting, it is spray-cast onto a high-speed rotating copper wheel and cooled to obtain an alloy strip.

[0088] Step 2: Qualitative characterization of amorphous structure using differential interference microscopy

[0089] The alloy strip prepared in step 1 was placed under a differential interference microscope to characterize the morphology of the free surface. Figure 7 As shown. Under differential interference microscopy, the free surface of the amorphous structure is completely smooth, while the crystal structure has a granular and rough morphology due to the shrinkage of the local volume and the difference in preferred orientation. Therefore, it can be easily and quickly compared to get Co 55 Ta 10 B 35 The sample with the composition has only a few grains precipitated on the surface, with an almost completely amorphous structure, while the Co 53 Ta 8 B 39 The sample has a large roughness and almost no smooth area, indicating a large degree of crystallization. The conclusions verified by transmission electron microscopy and X-ray diffractometer are consistent with the characterization results of the present invention, that is, Co 55 Ta 10 B 35 Has an almost completely amorphous structure, while Co 53 Ta 8 B 39 The degree of crystallization is high.

[0090] Step 3: Quantitative analysis of amorphous phase in samples

[0091] The height profile curve of the free surface of the sample prepared in step 1 was measured using a laser confocal microscope, and the second-order differential of the curve was taken. The results are as follows: Figure 8 As shown. The free surface of the amorphous structure has a relatively gentle second-order differential curve; while Co 53Ta 8 B 39 Since the sample is almost a fully crystalline structure, the second-order differential curve of its profile height curve fluctuates greatly.

[0092] Example 3

[0093] Based on a rapid screening method for amorphous alloys based on free surface morphology, this example uses laser additive manufacturing technology to prepare Cu 50 Zr 50 Whether the sample has crystallized is evaluated, and the process includes:

[0094] Step 1: Preparation of alloy samples

[0095] Weigh each element according to the nominal composition, and the purity of each element shall not be less than 99.0%. Mix the single elements weighed in proportion and put them into the vacuum arc melting furnace, and draw the vacuum to 5×10 -3 Pa, and then 0.05MPa of high-purity argon with a purity of 99.9% is introduced as a protective gas, the single element is smelted for 1 min, and the smelting is repeated 5 times to obtain the mother alloy.

[0096] Then the master alloy is prepared by gas atomization to prepare alloy powder. 50 Zr 50 The alloy ingot is placed in the melting furnace, and the vacuum is drawn to less than 10ppm. When the alloy is heated to melt, high-purity argon is filled in until the pressure reaches 0.05MPa, and then the heating is continued for 3 minutes; then the high-pressure jet valve is opened to fill in argon to make the pressure 3.5MPa, and the obtained alloy melt is poured into the tundish of the vacuum induction melting gas atomization powder making equipment. It should be noted that the tundish has been preheated to 1000℃ in advance. Then the melt poured into the tundish flows out to the atomization chamber along the guide pipe at the bottom, and the Cu is atomized and cooled to obtain Cu 50 Zr 50 Powder sample. Finally, the powder sample is sieved to obtain a particle size of 35 to 60 microns, thereby obtaining a powder suitable for laser additive manufacturing.

[0097] Solution 280ML equipment was used to 50 Zr 50 The powder was laser printed to prepare the sample. The laser power was 150W, the scanning speed was 1000mm / min, and the overlap rate was 15%. A 3mm thick 1045 steel plate was used as the laser additive manufacturing substrate. Finally, the prepared additive manufacturing sample was ultrasonically cleaned to remove the powder particles adhering to the surface.

[0098] Step 2: Qualitative characterization of amorphous structure using differential interference microscopy

[0099] The alloy sample prepared by additive manufacturing technology in step 1 was placed under differential interference microscopy to characterize the morphology of the free surface. The results are as follows: Fig. 9 As shown. The differential interference morphology of the free surface of the sample is mainly a smooth area of ​​amorphous structure, but there is a small amount of particle precipitation caused by crystallization. This is because the thermal conductivity of the upper layer of the sample gradually deteriorates with the increase of the thickness of the additive manufacturing layer, so some grains are precipitated. The conclusion is the same as the characterization result of the solution of the present invention after verification by transmission electron microscopy and X-ray diffractometer.

[0100] Step 3: Quantitative analysis of amorphous phase in samples

[0101] The surface height profile curve of the free surface of the sample prepared in step 1 was measured using a laser confocal microscope and plotted as a surface contour map. The results are shown in Fig.10 In addition to the gentle height fluctuations caused by laser printing, there are small areas of local height variations caused by particle precipitation on the sample surface, indicating a small degree of crystallization.

[0102] The crystallized area on the sample surface can be simply and clearly obtained from the contour map of the surface height profile curve; the relative size of the grains can also be obtained based on the size of the local height change area caused by the grains in the contour map.

[0103] Example 4

[0104] Based on a rapid screening method for amorphous alloys based on free surface morphology, this embodiment prepares Ni 60 Ta 40 Whether the sample has crystallized is evaluated, and the process includes:

[0105] Step 1: Preparation of film samples

[0106] High-purity target material with a purity of no less than 99.5% and single-crystal silicon as the coating substrate are used to prepare thin film samples. First, the vacuum is pumped to 5×10 -3 Pa, then the target is baked and the sample is prepared, with a power of 20KW.

[0107] Step 2: Qualitative characterization of amorphous structure using differential interference microscopy

[0108] The alloy sample prepared by additive manufacturing technology in step 1 was placed under differential interference microscopy to characterize the morphology of the free surface. The results are as follows: Fig.11 The differential interference morphology of the free surface of the sample is a completely smooth area, indicating that the film sample is a completely amorphous structure, which is related to the high cooling rate of the coating deposition. The transmission electron microscope and X-ray diffractometer also verified that the film sample is a completely amorphous structure.

[0109] In summary, the method provided by the present invention for rapidly screening amorphous alloy components and locating crystallization regions can rapidly and qualitatively identify amorphous components, quantitatively calculate the relative content of (amorphous) crystals and the relative size of grains, effectively locate crystallization regions, and compare the amorphous forming abilities of different components. There are no special requirements for the components of non-alloy systems, samples do not require complex pretreatment and tedious sample preparation, characterization time is short, and accuracy is high. Characterization costs can be effectively reduced, with the technical effect of reducing costs and increasing efficiency.

[0110] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for rapidly screening high-forming amorphous alloy components and locating crystallization regions, characterized in that: The following steps are involved: Preparation of alloy samples: obtaining alloy free surface; Qualitative identification of amorphous components: Place the free surface of the alloy under a microscope with a differential interference imaging module to observe the height difference of its differential interference microscopic morphology; Quantitative calculation of relative crystal content and relative grain size: including second-order differential statistical method of profile height or dark field phase observation method; Wherein, in the step of qualitatively identifying the amorphous component, a microscope with a differential interference imaging module is used, and the height difference of the local morphology observed is derived from the difference in the local crystallization degree of the sample: if the height difference of the morphology is manifested as no local height fluctuation, and the morphology is smooth and flowing, it is an amorphous structure; if the height difference of the morphology is manifested as obvious local height fluctuation, and the morphology is completely rough, it is a crystalline structure; if the height difference of the morphology is manifested as local fluctuation, contraction, or particles precipitated under a smooth substrate, it is a semi-amorphous structure; The second-order differential statistical method for profile height comprises the following steps: measuring the profile height of the free surface of the alloy, performing second-order differential calculation on the measured profile height curve to form a second-order differential curve, and performing statistics on the mutation range of the second-order differential curve; the profile height measurement of the free surface of the alloy includes line profile height and / or surface profile height, and the height profile measurement resolution can reach up to 20 nm; the second-order differential calculation formula is: , i=2,3,4,5……n, where As the second-order differential of the baseline length increases, are the corresponding height values ​​on the height profile curve, and n is the total number of points collected by the height profile curve; the mutation range of the second-order differential curve is ±0.1 of the ordinate axis, and the abscissa length of the fluctuation segment corresponding to the mutation range is counted, and its ratio to the total length of the baseline is obtained, and the result is the relative content of the crystalline phase in the direction of the baseline; The dark field phase observation method comprises the following steps: placing the free surface of the alloy under the dark field phase of an optical microscope for observation, and counting the proportion of the bright area to the total area of ​​the field of view; It also includes locating the crystallization area: using the second-order differential statistical method of profile height to analyze the position distribution of the fluctuation segment in the second-order differential curve of the free surface height profile, combined with the differential interference microscopic morphology image of its surface, the crystallization area can be quickly located.

2. The method for rapidly screening high-forming amorphous alloy components and locating crystallization regions according to claim 1, characterized in that: In the step of preparing the alloy sample, the surface roughness of the free surface of the alloy is obtained to be ≤100 μm.

3. The method for rapidly screening high-forming amorphous alloy components and locating crystallization regions according to any one of claims 1 to 2, characterized in that: The method is applicable to all amorphous alloy systems for rapid identification of amorphous components, calculation of the relative content of crystals and / or amorphous phases, and / or location of crystallization regions, and comparison of the amorphous forming abilities of different components, thereby screening amorphous alloy components with high forming ability, without the need for complicated sample preparation, with short characterization time and high accuracy.

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