CN1828282A - Neutron diffraction measure method for CaO-Al2O3-SiO2 system microcrystalline glass residue stress - Google Patents

Abstract

Wherein, first preparing the glass-ceramic; adjusting the neutron monochromator to select opposite monochromatic neutron; irradiating sample surface with neutron beam with diffraction angle 2theta as 10-75Deg; taking strain detection crystal face with principal crystalline phase as beta-wollastonite and obtaining the average strain result as: epsilon=1/3(epsilon11+epsilon22+epsilon33), opposite volume mean strain as delta=1/V(Integral of epsilondV); calculating with formulasigma=E/3(1-2v)delta (wherein, E: Young's modulus; v: Poisson's ratio), and then obtaining the total strain on three axial directions delta=ea+eb+ec; exactly, here, selecting E=70GPa and v=0.245; repeating former steps to obtain different residual strain values to draw distribution curve. This invention can obtain the inner strain of sample and fit to massive sample.

Description

CaO-Al 2O 3-SiO 2The neutron diffraction measuring method of system microcrystalline glass residue stress

Technical field

The present invention relates to a kind of neutron diffraction and measure microcrystalline glass residue stress method, particularly CaO-Al ₂O ₃-SiO ₂System glass ceramics specimen surface unrelieved stress neutron diffraction assay method.

Background technology

In recent years, both at home and abroad to the building decoration devitrified glass, promptly be the devitrified glass (CaO-Al of main crystalline phase (referring to Fig. 1) with β-wollastonite ₂O ₃-SiO ₂System) the research report is a lot, wherein more deep to the precipitation process research of wollastonite crystal, no matter inquire into, still from composition, Study of Effect Factors for Sythetic Technology, so that the devitrified glass Mechanical Properties all has been deep into certain depth to crystallization degree from Crystallization Mechanism.Along with CaO-Al ₂O ₃-SiO ₂The development of system glass ceramics industry in its commercial production, exists insoluble " distortion " or phenomenons such as " bursting ".The appearance of these problems can reduce the yield rate of product greatly, thereby has influence on the technical development of economic benefit of enterprises and industry.In addition, bring unsafe factor also can for user's use.Studying carefully it and produce reason, is owing to exist bigger structural stress and thermal stress in the middle of the devitrified glass.About problem in science such as structural stress in the devitrified glass and thermal stress are to be worth very much research.

At present aspect the research of the internal stress of material, metal material has had darker research, and theory is also fairly perfect.And the relevant stress problem in the Inorganic Non-metallic Materials has research, but the research degree of depth is not enough, and the stress that how to detect accurately and efficiently in the devitrified glass is very crucial.Aspect test stress, mainly adopt means of testing now such as polariscope, X ray measuring stress instrument, neutron diffraction stress ga(u)ge, ultrasound wave stress determination instrument both at home and abroad.

Patent 03155738.4 has been introduced the X ray stress test method.And relevant neutron diffraction method is to inorganic non-metallic, and particularly this test nontransparent, the polycrystalline material unrelieved stress of devitrified glass is not also introduced.

Common X-ray diffraction method test stress principle is simple, and therefore ray convenient sources economy be widely used.But the energy of its ray is lower, and penetration capacity is very weak, finds that stressor layers thickness is generally about 10 microns.Because the characteristic of the big degree of depth of neutron transmissive sample can record the sample internal stress, and be suitable for the bulk sample and measure, tool has an enormous advantage.Therefore, in order to improve the penetration depth of ray to sample, the present invention proposes neutron diffraction method test stress.

Summary of the invention

The object of the present invention is to provide a kind of sample residual stress measuring method that do not damage, promptly provide a kind of neutron diffraction method of utilizing CaO-Al ₂O ₃-SiO ₂The system glass ceramics internal stress is tested.

The neutron ray diffraction approach is a kind of method of testing of non-destructive, therefore, is very suitable method for the unrelieved stress of testing fragility and opaque material.The neutron diffraction method is similar with X-ray diffraction method, also be the stress state that object is calculated in the variation of measuring the material lattice constant, but the penetrability of neutron is strong, so can test the body stress distribution of bulk bulk sample.When wavelength is that the neutron current of λ is by a certain angle irradiation during to material surface, if Miller indices are the family of crystal planes space D of hkl in the irradiated site _HklJust be the integral multiple of λ, then constructive interference just can take place in Fan She neutron current.At this moment flowing angled ψ with incident neutron _HklThe detector place can receive a peak signal.Produce the angle and the crest width of constructive interference according to these, use Prague (Bragg) law: 2D _HklSin θ=n λ can obtain the average headway D of some family of crystal planes in the irradiated site _HklBecause unrelieved stress has changed the grating constant of material, thereby the spacing of same family of crystal planes (hkl) is when unstress state, and the spacing of measuring with neutron diffraction can become D _0hklSo the microstrain of lattice can be expressed as e in the irradiated site _Hkl=(D _Hkl-D _0hkl)/D _0hklWhen crystal structure known, as CaO-Al ₂O ₃-SiO ₂System glass ceramics is a principal crystalline phase with β-wollastonite, intensity and position that can analyzing crystal, and then can determine the grating constant of crystalline phase.And average micro-elasticity strain is e _a=(a-a ₀)/a ₀, a ₀Correspond to devitrified glass grating constant under standard grating constant and the stress with a.For CaO-Al ₂O ₃-SiO ₂The final stress value of system glass ceramics can be by formula: $\mathrm{\σ}=\frac{E}{3(1-2\mathrm{\υ})}\mathrm{\Δ}$ Calculate.In the formula, E is a Young modulus, and υ is a Poisson ratio, and Δ is i.e. three axial strain summation: the Δ=e of bulk strain _a+ e _b+ e _c, and then obtain the stress state of devitrified glass.The technical scheme that realizes above-mentioned purpose is:

A kind of CaO-Al ₂O ₃-SiO ₂The method of testing of system microcrystalline glass residue stress is characterized in that described method of testing is the neutron diffraction method, and test is carried out as follows:

Step 1.CaO-Al ₂O ₃-SiO ₂The preparation of system glass ceramics is SiO by devitrified glass composition percentage by weight ₂60～70%, Al ₂O ₃7～10%, CaO 18～20%, ZnO 5～7%, BaO 4～5%, Na ₂O+K ₂O 4～5%, B ₂O ₃1～3% and Sb ₂O ₃0.5～1% formulate glass raw material mixes, and makes CaO-Al through founding with crystallization ₂O ₃-SiO ₂System glass ceramics;

Step 2, by means of neutron diffractometer, supporting stress test program is adjusted neutron monochromator, chooses corresponding monochromatic neutron;

Step 3, step 1 is made CaO-Al ₂O ₃-SiO ₂What the system glass ceramics sample placed neutron diffractometer puts the test sample place, then utilizes Angle measurement to select measured zone and measurement point for bulk sample, and with the selected sample area of neutron beam incident; The fritter sample then directly places sample 10 * 70 millimeters of neutron beams ²In the area;

Step 4, neutron beam is shone specimen surface, detector scanning angle of diffraction 2 θ scopes: 10～75 °;

Step 5, to CaO-Al ₂O ₃-SiO ₂Carry out strain measurement ε in the system glass ceramics on the crystal face of different content principal crystalline phase β-wollastonite _Ij, detect from six direction at least;

Step 6, the ε that uses step 5 to measure _IjEach axial microstrain calculates the mean strain result:

$\stackrel{}{\stackrel{\‾}{\mathrm{\ϵ}}=}\frac{1}{3}({\mathrm{\ϵ}}_{11}+{\mathrm{\ϵ}}_{22}+{\mathrm{\ϵ}}_{33}),$ Corresponding volume averaging strain is:

$\mathrm{\Δ}=\frac{1}{V}{\∫}_V\stackrel{\‾}{\mathrm{\ϵ}}\mathrm{dV},$ In the formula; V is β-wollastonite crystal volume, ε ₁₁, ε ₂₂, ε ₃₃Be respectively the axial strain of crystal three;

Step 7, substitution stress formula $\mathrm{\σ}=\frac{E}{3(1-2\mathrm{\υ})}\mathrm{\Δ}$ Calculate, E is a Young modulus in the formula, and υ is a Poisson ratio,

Δ is bulk strain, i.e. three axial strain summation: Δ=e _a+ e _b+ e _cFor CaO-Al ₂O ₃-SiO ₂System glass ceramics, E=70GPa, stress value σ can be tried to achieve in υ=0.245;

Step 8, repeat above job step, test the unrelieved stress of various standard sample diverse locations, draw out the residual stress distribution curve of measured member

Described CaO-Al ₂O ₃-SiO ₂The preparation of system glass ceramics is after frit is fully mixed, to place in the ceramic crucible, puts into silicon molybdenum stove and is raised to 1450 ℃～1480 ℃ insulations after 〉=2 hours with 3 ℃/minute, and shrend becomes 0.5～6 millimeter glass particle, dry for standby.Frit is put into ready-made mould insert the high temperature experimental furnace and be raised to 1120 ℃ from room temperature, be incubated 〉=2 hours, the glass particle crystallization is shakeout, be cooled to room temperature, make the devitrified glass sample through annealing with 3 ℃/minute heating rate.

A kind of sample residual stress measuring method that do not damage provided by the invention is particularly useful for opaque Inorganic Non-metallic Materials.

The present invention adopts the neutron diffraction method that devitrified glass is carried out stress measurement.Because the characteristic of the big degree of depth of neutron transmission sample can record the sample internal stress, and be suitable for the bulk sample and measure, more common X-ray diffraction method test stress tool has an enormous advantage.

The neutron diffractometer that the present invention adopts is two other neutron powder diffractometers of China Atomic Energy Science Research Institute's heavy water research reactor.

Description of drawings

Fig. 1 is the diffracting spectrum of devitrified glass sample, and principal crystalline phase is β-CaSiO ₃

Fig. 2 is a neutron diffractometer stress test synoptic diagram.

Number in the figure title: 1-reactor, 2-neutron beam, 3-monochromator, 4-collimating apparatus, 5-observation port, 6-sample, 7-sample bench, 8-collimating apparatus, 9-detector.

Embodiment

Embodiment 1: prepare CaO-Al by aforesaid method ₂O ₃-SiO ₂System glass ceramics.

The frit of drying is put into ready-made mould inserts the high temperature experimental furnace and is raised to 1120 ℃ with 3 ℃/minute heating rate from room temperature, be incubated 2 hours, the glass particle crystallization is shakeout, be cooled to room temperature, make 20 millimeters * 20 millimeters * 8mm millimeter devitrified glass sample through annealing.Sample is divided into two: a specimen surface carries out grinding and polishing, the state that specimen surface keeps script to shakeout automatically.Neutron diffraction is measured on two other neutron powder diffraction instrument of China Atomic Energy Science Research Institute's heavy water research reactor and is carried out.The incident neutron wavelength is 0.1159 nanometer, and scattering angle is 25 °～105 °, 0.1 ° of step pitch, and the mode that adopts fixing incident neutron to count writes down the diffraction spectra of 4 detectors, and per step watchdog count is 10000, and the average used time is 2.75 minutes.Utilize Rietveld peak shape refine method that the neutron diffraction intensity data of each detector record is fitted.

Sample is put on the sample bench of Fig. 2 neutron beam irradiation specimen surface, detector scanning angle of diffraction 2 θ scopes: 10～75 °; (2 34) crystal face to β-wollastonite crystal carries out the accurate measurement peak position, and angle of diffraction 2 θ are near 69.6 °.

Crystal face constant under the test stress state calculates each axial microstrain, obtains the mean strain result and is: $\stackrel{\‾}{\mathrm{\ϵ}}=\frac{1}{3}({\mathrm{\ϵ}}_{11}+{\mathrm{\ϵ}}_{22}+{\mathrm{\ϵ}}_{33}).$ Corresponding volume averaging strain is $\mathrm{\Δ}=\frac{1}{V}{\∫}_V\stackrel{\‾}{\mathrm{\ϵ}}\mathrm{dV},$ The substitution stress formula $\mathrm{\σ}=\frac{E}{3(1-2\mathrm{\υ})}\mathrm{\Δ},$ Get E=70GPa, the stress value of surperficial machining and surperficial undressed sample can be tried to achieve in υ=0.245.

Embodiment 2: prepare CaO-Al by aforesaid method ₂O ₃-SiO ₂System glass ceramics.

The frit of drying is put into ready-made mould insert the high temperature experimental furnace and be raised to 1120 ℃ from room temperature, be incubated 2 hours, the glass particle crystallization is shakeout, different annealing rates is set with 3 ℃/minute heating rate.The sample for preparing different annealing schedules carries out stress test.Crystal face constant under the test stress state calculates each axial microstrain, obtains the mean strain result and is: $\stackrel{\‾}{\mathrm{\ϵ}}=\frac{1}{3}({\mathrm{\ϵ}}_{11}+{\mathrm{\ϵ}}_{22}+{\mathrm{\ϵ}}_{33}).$ Corresponding volume averaging strain is $\mathrm{\Δ}=\frac{1}{V}{\∫}_V\stackrel{\‾}{\mathrm{\ϵ}}\mathrm{dV},$ The substitution stress formula $\mathrm{\σ}=\frac{E}{3(1-2\mathrm{\υ})}\mathrm{\Δ},$ Can try to achieve the devitrified glass stress that makes under the different annealing rates.

Embodiment 3: prepare CaO-Al by aforesaid method ₂O ₃-SiO ₂System glass ceramics.Change CaO, the Al of devitrified glass ₂O ₃Content prepare the devitrified glass sample of different oxides.Crystal face constant under the test stress state calculates each axial microstrain, obtains the mean strain result and is: $\stackrel{\‾}{\mathrm{\ϵ}}=\frac{1}{3}({\mathrm{\ϵ}}_{11}+{\mathrm{\ϵ}}_{22}+{\mathrm{\ϵ}}_{33}).$ Corresponding volume averaging strain is $\mathrm{\Δ}=\frac{1}{V}{\∫}_V\stackrel{\‾}{\mathrm{\ϵ}}\mathrm{dV},$ The substitution stress formula $\mathrm{\σ}=\frac{E}{3(1-2\mathrm{\υ})}\mathrm{\Δ},$ Can try to achieve the devitrified glass stress value of different oxide contents.

Claims (1)

1. CaO-Al ₂O ₃-SiO ₂The method of testing of system microcrystalline glass residue stress is characterized in that described method of testing is the neutron diffraction method, and test is carried out as follows,

Step 1.CaO-Al ₂O ₃-SiO ₂The preparation of system glass ceramics is SiO by devitrified glass composition percentage by weight ₂60～70%, Al ₂O ₃7～10%, CaO 18～20%, and ZnO 5～7%, and BaO 4～5%, Na ₂O+K ₂O4～5%, B ₂O ₃1～3% and Sb ₂O ₃0.5～1% formulate glass raw material mixes, and makes CaO-Al through founding with crystallization ₂O ₃-SiO ₂System glass ceramics;

Step 2, by means of neutron diffractometer, supporting stress test program is adjusted neutron monochromator, chooses corresponding monochromatic neutron;

Step 3, step 1 is made CaO-Al ₂O ₃-SiO ₂What the system glass ceramics sample placed neutron diffractometer puts the test sample place, then utilizes Angle measurement to select measured zone and measurement point for bulk sample, and with the selected sample area of neutron beam incident; The fritter sample then directly places sample 10 * 70 millimeters of neutron beams ²In the area;

Step 4, neutron beam is shone specimen surface, detector scanning angle of diffraction 2 θ scopes: 10～75 °;

Step 5, to CaO-Al ₂O ₃-SiO ₂Carry out strain measurement ε in the system glass ceramics on the crystal face of different content principal crystalline phase β-wollastonite _Ij, detect from six direction at least;

Step 6, the ε that uses step 5 to measure _IjEach axial microstrain calculates the mean strain result: $\stackrel{\‾}{\mathrm{\ϵ}}=\frac{1}{3}({\mathrm{\ϵ}}_{11}+{\mathrm{\ϵ}}_{22}+{\mathrm{\ϵ}}_{33}),$ Corresponding volume averaging strain is: $\mathrm{\Δ}=\frac{1}{V}{\∫}_V\stackrel{\‾}{\mathrm{\ϵ}}\mathrm{dV},$ In the formula; V is β-wollastonite crystal volume, ε ₁₁, ε ₂₂, ε ₃₃Be respectively the axial strain of crystal three;

Step 7, substitution stress formula $\mathrm{\σ}=\frac{E}{3(1-2\mathrm{\υ})}\mathrm{\Δ}$ Calculate, E is a Young modulus in the formula, and ν is a Poisson ratio,

Δ is bulk strain, i.e. three axial strain summation: Δ=e _a+ e _b+ e _cFor CaO-Al ₂O ₃-SiO ₂System glass ceramics, E=70GPa, stress value σ can be tried to achieve in ν=0.245;

Step 8, repeat above job step, test the unrelieved stress of various standard sample diverse locations, draw out the residual stress distribution curve of measured member.

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