Neutron diffraction equipment for residual stress detection in metal additive manufacturing processes

Abstract

The present invention discloses a neutron diffraction device for residual stress detection in a metal additive manufacturing process, comprising a detection mechanism, which includes a neutron beam generating device and a plurality of diffraction detection devices. The neutron beam generating device is used to emit an incident neutron beam, and the diffraction detection device is located on the side of the incident neutron beam. The incident neutron beam irradiates the workpiece and diffracts to generate a plurality of outgoing neutron beams perpendicular to the incident neutron beam, and the diffraction detection device receives the outgoing neutron beam. The detection mechanism is provided with a plurality of diffraction detection array devices. Each detection array can simultaneously collect diffraction data of a plurality of diffraction peaks through the time-of-flight method, providing a data basis for multi-peak full spectrum analysis. The analysis data can also obtain lattice strain, phase change, and organizational structure information of different crystal planes.

Description

Technical Field

[0001] The present invention relates to the field of neutron diffraction technology, and in particular to a neutron diffraction device for detecting residual stress in a metal additive manufacturing process. Background Art

[0002] Additive manufacturing technology for metal structures uses alloy powder or wire as raw material. Through in-situ metallurgical melting using a high-power heat source, rapid solidification, and layer-by-layer deposition, this technology creates near-net-shape shapes of fully dense, high-performance, large, complex metal structures directly from a digital model. This technology offers a range of technical advantages, including a shortened manufacturing process, high material utilization, and low cost.

[0003] Metal additive manufacturing (AM) technology possesses the inherent properties of "micro-area supermetallurgy" and "quenched rapid solidification." During the AM process, a series of complex metallurgical, physical, chemical, and thermomechanical coupling processes occur within the material, including multiple transfers of heat, mass, and momentum, as well as rapid liquid solidification under high temperature gradients. The resulting material microstructure is complex. Dynamic, real-time monitoring and control of the evolution of defects, stresses, and microstructures during AM remain both a challenging and hot topic at the forefront of international research.

[0004] Neutron diffraction technology can be used to determine the internal stress and texture of engineering material components, conduct phase analysis, obtain statistical average experimental results of the internal microstructural information of large samples, and establish the intrinsic relationship between microstructure and macroscopic performance. One of its unique advantages is the ability to perform in-situ testing and analysis of materials during sample preparation, obtaining information that is difficult to obtain under conventional conditions.

[0005] There are currently no public reports on the use of neutron diffraction technology to detect stress and structural evolution during additive manufacturing. Summary of the Invention

[0006] In order to solve the problem of neutron diffraction detection of residual stress in the additive manufacturing process, the purpose of the present invention is to provide a neutron diffraction device for residual stress detection in the metal additive manufacturing process, so as to solve the problem of neutron diffraction detection of residual stress in the additive manufacturing process.

[0007] The purpose of the present invention is achieved by adopting the following technical solutions:

[0008] A neutron diffraction device for residual stress detection in a metal additive manufacturing process comprises a detection mechanism including a neutron beam generating device and a plurality of diffraction detection devices;

[0009] The neutron beam generating device is used to emit an incident neutron beam, and the diffraction detection device is located on the side of the incident neutron beam. The incident neutron beam irradiates the workpiece and diffracts to generate multiple outgoing neutron beams perpendicular to the incident neutron beam, and the diffraction detection device receives the outgoing neutron beam.

[0010] In some optional embodiments, the neutron beam generating device is provided with an entrance hole for limiting the cross-sectional area of ​​the incident neutron beam.

[0011] In some optional embodiments, the diffraction detection device includes a radial collimator and a diffraction detector arranged in sequence along the irradiation direction of the outgoing neutron beam, and the outgoing neutron beam passes through the radial collimator and irradiates the diffraction detector.

[0012] In some optional embodiments, the system further includes a substrate for placing the workpiece, wherein a first strain sensor is provided on the substrate.

[0013] In some optional embodiments, a first temperature sensor is provided on the substrate.

[0014] In some optional embodiments, a driving mechanism is further included, which includes a first driving component for driving the detection mechanism and the workpiece to move relative to each other along the X-axis direction, a second driving component for driving the detection mechanism and the workpiece to move relative to each other along the Y-axis direction, a third driving component for driving the detection mechanism and the workpiece to move relative to each other along the Z-axis direction, and a fourth driving component for driving the detection mechanism and the workpiece to rotate relative to each other around the Z-axis; the X-axis, Y-axis and Z-axis are coordinate axes of a rectangular coordinate system, and the X-axis and Y-axis are both parallel to the end face of the workpiece.

[0015] In some optional embodiments, a control device is further included, and the control device is electrically connected to the diffraction detection device, the first drive assembly, the second drive assembly, the third drive assembly and the fourth drive assembly respectively.

[0016] In some optional embodiments, a data storage device is further included, and the data storage device is electrically connected to the control device.

[0017] In some optional embodiments, there are two diffraction detection devices, which are respectively recorded as a first diffraction detection device and a second diffraction detection device. The first diffraction detection device and the second diffraction detection device are arranged opposite to each other and are respectively located on both sides of the incident neutron beam.

[0018] In some optional embodiments, a second strain sensor and a second temperature sensor are provided on the workpiece.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The detection mechanism is equipped with multiple diffraction detection devices, which are located on the side of the incident neutron beam and are used to receive the outgoing neutron beam to simultaneously collect diffraction data of multiple diffraction peaks, providing a data basis for multi-peak full spectrum analysis, and can also obtain lattice strain, phase change, and organizational structure information of different crystal planes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the invented neutron diffraction device for residual stress detection in metal additive manufacturing process;

[0022] Figure 2 The second schematic diagram of the structure of the invented neutron diffraction device for residual stress detection in metal additive manufacturing process;

[0023] In the picture:

[0024] 10. Neutron beam generating device; 11. Entrance aperture; 12. Spallation neutron source; 20. Diffraction detection device; 21. Radial collimator; 22. Diffraction detector; 30. Incident neutron beam; 40. Outgoing neutron beam; 50. Substrate; 51. First strain sensor; 52. First temperature sensor; 60. Workpiece; 61. Second strain sensor; 62. Second temperature sensor; 70. Molten pool; 80. Processing head; 90. Neutron diffraction detection point. DETAILED DESCRIPTION

[0025] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0026] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Example 1

[0029] Combine Figure 1 and Figure 2 As shown, the neutron diffraction device for residual stress detection in the metal additive manufacturing process of the present invention is schematically shown, which is applied to metal additive manufacturing.

[0030] A neutron diffraction device for residual stress detection in a metal additive manufacturing process includes a detection mechanism, which includes a neutron beam generating device 10 and multiple diffraction detection devices 20. The neutron beam generating device 10 is capable of emitting an incident neutron beam 30, which is directed toward a workpiece 60. The incident neutron beam 30 irradiates the workpiece 60 and diffracts to produce multiple outgoing neutron beams 40, wherein the outgoing neutron beams 40 are perpendicular to the incident neutron beam 30.

[0031] The diffraction detection device 20 is positioned to the side of the incident neutron beam 30 and is used to receive the outgoing neutron beam 40 to perform neutron diffraction measurements. Of course, multiple diffraction detection devices 20 can be positioned opposite each other or evenly distributed around the incident neutron beam 30. Multiple diffraction detection devices 20 can perform neutron diffraction measurements in multiple directions, simultaneously collecting diffraction data for multiple diffraction peaks. This provides the data foundation for multi-peak full spectrum analysis and can also provide information on lattice strain, phase transitions, and microstructures on different crystal planes.

[0032] The neutron beam generating device 10 is provided with a spallation neutron source 12 for producing a neutron beam. The neutron beam generating device 10 also has an entrance aperture 11 for limiting the cross-sectional area of ​​the incident neutron beam 30. The diffraction detection device 20 includes a radial collimator 21 and a diffraction detector 22 arranged in sequence along the irradiation direction of the outgoing neutron beam 40. The outgoing neutron beam 40 passes through the radial collimator 21 and irradiates the diffraction detector 22. The radial collimator 21 is used to limit the width of the outgoing neutron beam 40. The radial collimator 21 and the entrance aperture 11 cooperate to determine the size of the neutron sampling measurement volume. That is, the volume of the intersection of the incident neutron beam 30 and the outgoing neutron beam 40 is the sampling measurement volume. The neutron sampling measurement volume is 2×2×2mm. 3 -8×8×8mm 3 .

[0033] Preferably, there are two diffraction detection devices 20 and they are respectively recorded as the first diffraction detection device 20 and the second diffraction detection device 20. The first diffraction detection device 20 and the second diffraction detection device 20 are arranged opposite to each other and are respectively located on both sides of the incident neutron beam 30. The first diffraction detection device 20 and the second diffraction detection device 20 respectively correspond to two orthogonal residual strain directions.

[0034] Example 2

[0035] The metal workpiece 60 faces the following problems during the additive manufacturing process: long-term periodic intense heating and cooling, and contraction under the influence of mechanical constraints around the part, resulting in large and complex residual stresses inside the workpiece 60, including thermal stress, structural stress, and mechanical constraint stress, which often lead to severe deformation and cracking of the workpiece 60. Currently, there is a lack of quantitative direct experimental data on the residual stress and its evolution during the forming process.

[0036] This embodiment differs from Example 1 in that the neutron diffraction device for residual stress detection during metal additive manufacturing also includes a substrate 50 for placing a workpiece 60. A first strain sensor 51 and a first temperature sensor 52 are provided on the substrate 50, while a second strain sensor 61 and a second temperature sensor 62 are provided on the workpiece 60. In this embodiment, an additive manufacturing processing head 80 is driven by an existing mobile device, enabling movement relative to the substrate 50 (or workpiece 60) to achieve additive manufacturing. A neutron diffraction detection point 90 of the neutron diffraction device for residual stress detection during metal additive manufacturing is located at a fixed position on the workpiece 60. This structure enables the neutron diffraction device for residual stress detection during metal additive manufacturing to analyze information on temperature-dependent lattice parameter changes in the workpiece 60 material, information on solid-state phase transformations and their evolution over time, information on the temporal evolution of residual strain and lattice strain, and information on the temporal evolution of preferred orientation of some grains. The experimental data can help to gain a deeper understanding of the generation and evolution behavior mechanism of residual stress in metal additive manufacturing, and thus help to control the deformation and cracking of the workpiece 60.

[0037] Combine Figure 1 As shown, workpiece 60 is a flat sample. Considering that the mechanical constraint of substrate 50 on workpiece 60 will generate significant residual stress, neutron diffraction detection point 90 can be selected near the bottom of workpiece 60. The collected neutron diffraction data is used to analyze the thermal stress and phase change of workpiece 60 during the layer-by-layer accumulation process. The first temperature sensor 52 is used to monitor the temperature of substrate 50, the first strain sensor 51 is used to monitor the macroscopic residual strain information of substrate 50, and the second temperature sensor 62 is used to detect the temperature of workpiece 60, and the second strain sensor 61 is used to monitor the macroscopic residual strain information of workpiece 60. The temperature information and macroscopic residual strain information collected by the first strain sensor 51, first temperature sensor 52, second strain sensor 61, and second temperature sensor 62 are used to assist in the analysis of neutron experimental data.

[0038] During neutron diffraction data collection, a neutron diffraction detection point 90 is selected on a workpiece 60 that has been machined to a certain height. The additive manufacturing processing head 80 begins printing and preparing the workpiece 60 from the starting end and gradually moves to the final end. During this time, the neutron diffraction equipment used for residual stress detection in the metal additive manufacturing process monitors and collects neutron diffraction data at the neutron diffraction detection point 90 in real time. During neutron diffraction data analysis, the data is segmented by minute to ensure sufficient diffraction intensity for diffraction signal analysis.

[0039] Example 3

[0040] The following problems exist in the additive manufacturing forming process of the metal workpiece 60: the molten pool 70 undergoes a non-equilibrium rapid solidification nucleation and crystallization growth process under the action of an ultra-high temperature gradient. During the rapid forming process, there is a lack of quantitative direct experimental data on key information such as the crystal structure, phase change, and strain near the molten pool 70, which brings great difficulties to the consistency control of the internal structure and mechanical properties of the formed workpiece 60.

[0041] The difference between this embodiment and embodiment 1 is that the neutron diffraction device for residual stress detection in the metal additive manufacturing process also includes a driving mechanism (not shown), which includes a first driving assembly for driving the detection mechanism and the workpiece 60 to move relative to each other along the X-axis direction, a second driving assembly for driving the detection mechanism and the workpiece 60 to move relative to each other along the Y-axis direction, a third driving assembly for driving the detection mechanism and the workpiece 60 to move relative to each other along the Z-axis direction, and a fourth driving assembly for driving the detection mechanism and the workpiece 60 to rotate relative to each other around the Z-axis. Wherein, the X-axis, Y-axis and Z-axis are coordinate axes of a rectangular coordinate system, and the X-axis and Y-axis are parallel to the end face of the workpiece 60. The first driving assembly, the second driving assembly and the third driving assembly can be an existing guide rail slide mechanism or an existing robotic arm mechanism. Based on the structure of the driving mechanism, the movement of the workpiece 60 relative to the detection mechanism can be achieved.

[0042] Combine Figure 2As shown, in this embodiment, the relative positions of the additive manufacturing processing head 80 and the detection mechanism are fixed. During the additive manufacturing process, the workpiece 60 is driven by the driving mechanism to grow layer by layer. The additive manufacturing processing head 80 forms a molten pool 70 on the workpiece 60. The neutron diffraction detection point 90 of the neutron diffraction device for residual stress detection in the metal additive manufacturing process is located on one side of the molten pool 70. As the molten pool 70 moves on the workpiece 60, the neutron diffraction detection point 90 also moves accordingly to maintain the relative position between the molten pool 70 and the neutron diffraction detection point 90. The position remains unchanged so as to always obtain the neutron diffraction information of the workpiece 60 in the semi-solidified area near the molten pool 70. The collection time is 1 minute to obtain neutron diffraction data of sufficient intensity. After the workpiece 60 is additively manufactured, what is collected is the average statistical diffraction information of the semi-solidified workpiece 60 at different positions within the 1-minute measurement time. Then, the relative position of the neutron diffraction detection point 90 and the molten pool 70 is changed, and the measurement of the next sampling point is continued. The diffraction information of the workpiece 60 near the molten pool 70 and at the far end of the molten pool 70 can be successively obtained for the research and analysis of strain and phase change.

[0043] Based on the structure of the neutron diffraction equipment used for residual stress detection in the metal additive manufacturing process, neutron diffraction can be used to observe the initial solidification area, semi-molten and semi-solidified area, solidification area, and cooling area near the molten pool 70, and obtain direct evidence such as solidification crystallization and diffraction signals, which is helpful for in-depth research on the solidification evolution behavior mechanism of the metal molten pool 70.

[0044] In addition, the neutron diffraction equipment used for residual stress detection in the metal additive manufacturing process also includes a control device and a data storage device. The control device is electrically connected to the data storage device, the diffraction detection device 20, the first drive component, the second drive component, the third drive component and the fourth drive component, respectively. The control device collects the neutron diffraction signal of the diffraction detection device 20 and sends the neutron diffraction signal to the data storage device for storage. The control device can also control the movement of the first drive component, the second drive component, the third drive component and the fourth drive component to drive the workpiece 60 to move relative to the detection mechanism.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The detection mechanism is provided with a plurality of diffraction detection devices 20, which are located on the side of the incident neutron beam 30 and are used to receive the outgoing neutron beam 40 to simultaneously collect diffraction data of multiple diffraction peaks, providing a data basis for multi-peak full spectrum analysis, and can also obtain lattice strain, phase change, and organizational structure information of different crystal planes.

[0047] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A neutron diffraction device for residual stress detection in metal additive manufacturing process, characterized in that: The device comprises a detection mechanism, the detection mechanism including a neutron beam generating device and a plurality of diffraction detection devices; the neutron beam generating device is used to emit an incident neutron beam, the diffraction detection devices are located to the side of the incident neutron beam, the incident neutron beam irradiates the workpiece and diffracts to generate a plurality of outgoing neutron beams perpendicular to the incident neutron beam, and the diffraction detection devices receive the outgoing neutron beams; The invention also includes a substrate for placing a workpiece, wherein the substrate is provided with a first strain sensor; the substrate is provided with a first temperature sensor; and the workpiece is provided with a second strain sensor and a second temperature sensor; It also includes a driving mechanism, which includes a first driving component for driving the detection mechanism and the workpiece to move relative to each other along the X-axis direction, a second driving component for driving the detection mechanism and the workpiece to move relative to each other along the Y-axis direction, a third driving component for driving the detection mechanism and the workpiece to move relative to each other along the Z-axis direction, and a fourth driving component for driving the detection mechanism and the workpiece to rotate relative to each other around the Z-axis; the X-axis, Y-axis and Z-axis are coordinate axes of a rectangular coordinate system, and the X-axis and Y-axis are both parallel to the end face of the workpiece.

2. The neutron diffraction device for residual stress detection in metal additive manufacturing according to claim 1, characterized in that: The neutron beam generating device is provided with an incident aperture for limiting the cross-sectional area of ​​the incident neutron beam.

3. The neutron diffraction device for residual stress detection in metal additive manufacturing according to claim 1, characterized in that: The diffraction detection device includes a radial collimator and a diffraction detector which are sequentially arranged along the irradiation direction of the outgoing neutron beam. The outgoing neutron beam passes through the radial collimator and irradiates the diffraction detector.

4. The neutron diffraction device for residual stress detection in metal additive manufacturing according to claim 1, characterized in that: It also includes a control device, which is electrically connected to the diffraction detection device, the first drive component, the second drive component, the third drive component and the fourth drive component.

5. The neutron diffraction device for residual stress detection in metal additive manufacturing process according to claim 4, characterized in that: The device further comprises a data storage device, wherein the data storage device is electrically connected to the control device.

6. The neutron diffraction device for residual stress detection in metal additive manufacturing process according to claim 1, characterized in that: There are two diffraction detection devices, which are respectively referred to as a first diffraction detection device and a second diffraction detection device. The first diffraction detection device and the second diffraction detection device are arranged opposite to each other and are respectively located on both sides of the incident neutron beam.

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