Neutron scattering low temperature stretching Dewar

Abstract

The invention discloses a neutron scattering low temperature stretching Dewar. A vacuum-pumping interface and a vacuum valve are arranged on a non-magnetic housing; a cooling panel is arranged in thenon-magnetic housing; two oxygen-free copper chucks arranged opposite to each other are arranged in the cooling panel; a first-stage cooling head of a closed-loop GM refrigerator is connected to a copper cooling panel; a second-stage cooling head of the closed-loop GM refrigerator is connected to the chucks through soft copper braids; a circular opening is formed on the cooling panel to allow a neutron beam to enter onto a sample; a thermometer and a heater are arranged at the second-stage cooling head; one end of the chucks is connected with a force sensor through a G10 glass fiber reinforcedplastic rod, and then connected with a highly precise loading stepping motor through a loading rod; and aluminum windows are arranged on both the front surface and the rear surface of the non-magnetic housing. According to the neutron scattering low temperature stretching Dewar, the sample can be kept in a loading state under a low-temperature environment. In addition, the system can be embeddedinto the neutron beam, and a special window of the system allows the neutron beam to be irradiated on the sample, so that the strain inside the loaded sample is achieved under a low-temperature and the stress is measured in real time.

Description

technical field [0001] The invention belongs to the technical field of real-time measurement of strain and stress inside a loaded sample in a low-temperature environment, and in particular relates to a neutron scattering low-temperature stretching Dewar. Background technique [0002] The background technology of the present invention mainly has two aspects, one is the tensile deformation loading technology of materials in low temperature environment, and the second is the deformation technology inside materials measured by neutron diffraction at normal temperature. [0003] For the deformation loading technology of materials in low temperature environment (see figure 1 ), at present, the samples are mainly immersed in cryogenic liquid nitrogen, liquid helium and other coolants, and the samples are cooled by heat conduction. Grips hold the sample and load it in tension through the testing machine. The main disadvantage is that the ambient temperature of the sample is single...

AI Technical Summary

Problems solved by technology

The main disadvantage is that the ambient temperature of the sample is single, and the temperature of the sample is the same as that of the coolant, which is inconvenient to adjust, and it is difficult to study the mechanical properties of materials at different temperatures and in variable temperature environments; the deformation of the sample can only be measured by the extensometer. The local surface strain is measured by sticking a low-temperature strain gauge on the surface, and the strain state inside the sample cannot be measured

[0004] For neutron diffraction techniques (see figure 2 ), the main principle is that the neutron beam from the neutron source is directly irradiated on the sample. At this time, the position of the Bragg diffraction peak of the material reflects the internal lattice spacing of the material. By measuring the change of the internal lattice spacing of the material, the material's Internal deformation and stress state, the disadvantage is that this technology is currently mainly used to measure the internal deformation of samples in a normal temperature environment. There is no domestic use of this technology to measure the internal strain and stress state of samples under low temperature conditions, especially under low temperature loading conditions.

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