JPH0714873Y2 - X-ray diffraction measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray diffraction measuring device for use in, for example, measuring retained austenite in a steel material.

A conventional X-ray diffraction measurement apparatus scans one X-ray detector along an arcuate trajectory centered on the sample,
It was a structure for measuring the relationship between the diffraction angle and the intensity. However, using such an apparatus, for example, when a chromium target X-ray tube that is not disturbed by the fluorescent X-rays of iron is used to detect residual austenite of steel, the diffraction angle 2θ of martensite, which is the α phase, is used. Is 155.8 degrees and the diffraction angle of γ-phase austenite is 128.2 degrees. That is, the angle between the diffraction line by martensite and the projected X-ray is only slightly over 20 degrees. Therefore, in order to prevent the diffraction rays or projected X-rays from being blocked by the edges of the X-ray tube or the detector, the radius of the sample, the X-ray source and the arcuate orbit must be sufficiently large. For this reason, there is a drawback that it is difficult to accurately detect the diffraction line of austenite having a weak intensity. Therefore, the present invention eliminates the above-mentioned drawbacks and can easily detect X-rays having a large diffraction angle.
It is intended to provide a device capable of accurately detecting the intensity.

The present invention does not rely on the structure of measuring the diffraction angle by moving one detector along one arcuate trajectory as in the conventional device, but instead of using a plurality of position sensitive X-ray detectors. X-rays within a suitable diffraction angle range are detected by using the X-ray detector, and the distance between the X-ray detector on the larger diffraction angle side and the sample surface is the same as that on the smaller diffraction angle side and the sample surface. It is designed to be larger than the distance. That is, the X-ray detector having a large diffraction angle is arranged at a position where the distance between the X-ray and the sample is large, so that the angle range where the projected X-rays are blocked at the edge of the detector is sufficiently small, By making it possible to perform measurement over a wide angle range and reducing the distance between the detector and the sample for X-rays having a small diffraction angle, there is an effect that the intensity can be accurately measured. The difference in detection sensitivity due to the difference in distance between the detector and the sample can be corrected without delay by using an electronic calculator together.

FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is a right side view thereof. If necessary, a collimator 1 whose inside is exhausted by a pump is used, for example, from a chrome target X-ray tube 2 to steel or the like. A thin parallel X-ray is made incident on a point p on the sample 3.
The fine adjustment arm 5 is moved by the axis 4 perpendicular to the plane of the drawing through this point p.
1 and 6 are supported so as to be independently rotatable, and position-sensitive X-ray detectors 7 and 8 are attached to the other ends of the arms 5 and 6, respectively. Each of the detectors 7 and 8 has a strip-shaped X-ray window 9 on the surface facing the sample 3, and the position of the X-ray incident on this window, that is, the incident point in the longitudinal direction of the window and the signal corresponding to the intensity thereof are detected. Send out. The arm 5,
6 is not shown, but the detector can
It is equipped with a mechanism that adjusts the position of 7 and 8 and is fixed, and is kept in a fixed state during measurement. The detector 7 detects the X-rays diffracted in the range of the angle A from the point p on the sample 3 as shown by the broken line, and the detector 8 detects the diffracted lines in the range of the angle B. The former is The point 1 is located at a sufficiently large distance 1 from the point p, and the latter is located at an appropriately smaller distance m. First
Angle D in the figure is the angle between the measurement limit of the detector 7 near the X-ray tube 2 and the projected X-ray, and angle C is the measurement limit of the detector 8 near the X-ray tube 2. This is the angle formed by the projected X-rays. The maximum diffraction angles that can be detected by the detectors 7 and 8 are (π-D) and (π-D), respectively.
C), and the minimum detectable diffraction angles are {π- (D + A)} and {π- (C + B)}, respectively.
Since (C + B) = π / 2 in this embodiment, the minimum diffraction angle that the detector 8 can detect is π / 2.
Here, if C is designed to be smaller than (D + A), the maximum diffraction angle (π−C) that can be detected by the detector 8 exceeds the minimum diffraction angle {π− (D + A)} that can be detected by the detector 7. As a result, the diffraction angle changes from π / 2 to (π−
All the diffracted X-rays within the range of D) are detected by the detector 7 or 8
Can be detected by any of the following.

As described above, since the X-ray diffraction measuring apparatus of the present invention uses a plurality of position-sensitive X-ray detectors, one of them, for example, 7 is arranged at a position of a sufficiently large distance 1 from the sample 3 to detect this. The angle D that cannot be detected due to the collision between the end 7'of the container and the collimator 1 can be made sufficiently small. In addition, the distance from the detector 7 to the sample 3 is determined by the X-ray tube 2
If the distance is larger than the distance from the sample to the sample 3, the angle D can be made sufficiently small to the position where the diffraction line is shielded at the edge portion of the X-ray tube 2. Moreover, by arranging the other detector 8 or the like at a position sufficiently close to the sample, it becomes possible to detect a weak diffraction line with high sensitivity.
An example in which such an example is applied to the measurement of retained austenite of steel will be described below. When carbon steel is quenched from the γ-phase austenite state, it mostly transforms into α-phase martensite, but γ-phase austenite may remain. This is called residual austenite, and there is a demand for controlling the volume ratio of this residual austenite in gears and tool steels. To measure the volume fraction of this retained austenite by X-ray diffraction, the α phase martensite (211)
The integrated intensity of the profile of the diffraction line from the plane and the integrated intensity of the profile of the diffraction line from the (220) plane of the γ-phase austenite may be compared. Therefore, when the above-mentioned embodiment is applied to the measurement of this retained austenite, the diffraction line from the α-phase martensite (diffraction angle 2θ = 155.8 degrees)
Can be detected by the detector 7, and the diffraction line (diffraction angle 2θ = 128.2 degrees) from the γ-phase austenite can be detected by the detector 8. Since the detector 7 is arranged at a position far from the sample 3, the detector 7 does not collide with the collimator 1 even when measuring a large diffraction angle such as 2θ = 155.8 degrees. Since the intensity of the diffraction line from the α-phase martensite is comparatively strong, the detection accuracy does not decrease so much even if the detector 7 is far away. On the other hand, the intensity of the diffracted rays from the γ-phase overstate is comparatively weak, so the detector 8
It is possible to perform highly accurate measurement by bringing the sample 3 closer to the sample 3 than the detector 7. Since the detector 8 is located at a position for measuring a diffraction line of 2θ = 128.2 degrees and is apart from the collimator 1, there is no concern that the detector 8 will collide with the collimator 1 even if the detector 8 is brought close to the sample 3. . The difference in detection sensitivity based on the distance between the detector and the sample may be corrected by an electronic calculator. According to this example, it is possible to measure even a sample having a volume ratio of retained austenite of about 1%. Moreover, since it is not necessary to mechanically move the detector to perform the measurement, the time required for the measurement is significantly shortened.

[Brief description of drawings]

FIG. 1 is a front view of the embodiment of the present invention, and FIG. 2 is a right side view of the apparatus of FIG. In the figure, 1 is a collimator,
2 is an X-ray tube, 3 is a sample, 4 is an axis, 5 and 6 are fine adjustment arms, 7 and 8 are position-sensitive X-ray detectors, and 9 is an X-ray window.

Claims (1)

[Scope of utility model registration request] 1. A slender collimator for injecting a thin parallel X-ray having a predetermined wavelength on a sample surface and a plurality of position-sensitive X-rays for detecting the diffraction angles of X-rays diffracted in a desired plane on the sample surface. A detector, and the distance between the X-ray detector on the larger diffraction angle side of the plurality of X-ray detectors and the sample surface is smaller than that of the X-ray detector on the smaller diffraction angle side and the sample surface. An X-ray diffraction measuring device characterized in that it is larger than the distance.