Short-wavelength X-ray diffraction plate-like internal stress fixed-point non-destructive testing method

Abstract

Residual stress is generated inside a polycrystalline material after the polycrystalline material (such as aluminum alloy and steel) is machined. The invention provides a short-wavelength X-ray diffraction plate-like internal stress fixed-point non-destructive testing method aiming at a polycrystalline plate-like material or plate-like workpiece with a weak texture by utilizing a short-wavelength X-ray diffraction instrument. The method is used for directly measuring a certain (hkl) crystal face diffraction spectrum in a plurality of phi angle (wherein phi is more than or equal to 45 degrees and less than or equal to 90 degrees) directions, and calculating based on the Bragg principle and a stress-strain relationship of in the generalized Hooke's law to obtain the stress of a measured part in the measured direction. With the method, through the translation of X, Y and Z, the stress of the other part can be measured; the stress in the other direction can be measured by allowing the plate-like material or plate-like workpiece to rotate around the normal of a plate surface. For the polycrystalline plate-like material or plate-like workpiece with the weak texture, the stress of any part inside the polycrystalline plate-like material or plate-like workpiece in any direction of an XY plane can be measured.

Description

technical field [0001] The invention relates to a fixed-point non-destructive detection method for the internal stress of a plate-shaped sample that does not require a stress-free standard sample by using short-wavelength characteristic X-ray diffraction, and is suitable for the internal stress of plate-shaped materials and workpieces prepared from polycrystalline materials with weak textures. and nondestructive testing of its distribution. Background technique [0002] Polycrystalline materials (such as aluminum alloy, steel, etc.) often generate large residual stress inside the polycrystalline material due to uneven plastic deformation after pressure processing, heat treatment, welding, casting, etc. , resulting in deformation due to rebalancing of internal residual stress, and the degree of deformation is directly related to the internal residual stress and its distribution of the material before machining. Not only that, the mechanical properties of the material / workpie...

AI Technical Summary

Problems solved by technology

The usual X-ray diffraction method, using an ordinary X-ray tube, can only non-destructively measure the average stress of the material / workpiece surface with a thickness of about 10 microns, that is, the usual X-ray diffraction method can only non-destructively measure the surface stress

To non-destructively measure the internal stress of materials / workpieces, neutron diffraction of nuclear reactors or short-wavelength X-ray diffraction of high-energy synchrotron radiation is usually used. However, the cost and maintenance costs of these two devices are high, and in the world, using The method of nondestructively measuring the internal stress of materials / workpieces by using neutron diffraction to prepare stress-free standard sample technology is relatively mature, and the testing and research of using these two methods to nondestructively measure the internal stress of materials / workpieces in my country is still in progress

Among the disclosed test methods for short-wavelength X-ray instruments using heavy metal target X-ray tubes as the radiation source, the invention patent application number ZL201010586489.7 also discloses a fixed-point non-destructive testing method for the internal inspection of rolled aluminum alloy plates. The method of rolling residual stress and lateral residual stress, which adopts W target X-ray tube radiation, and obtains the reference original interplanar spacing d through the prepared stress-free standard sample 0 , measure the rolling direction and transverse strain, and calculate the rolling direction residual stress and transverse residual stress inside the rolled plate. This method needs to prepare a stress-free standard sample, which is not only labor-intensive and time-consuming, but also difficult to ensure the internal residual stress of the prepared stress-free standard sample. The value is zero, which increases the test error and affects the non-destructive testing of the internal residual stress of the material / workpiece

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