中性子回折によるセラミックス内部の応力測定

概要

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The neutron diffraction method is a useful nondestructive technique to measure the internal stress distributed within a ceramic component because the neutron penetration depth for ceramics is more than one millimeter. The diffraction from the Si_3N_4 (321) plane by monochromatic neutrons (wavelength λ=1.99Å) was used for stress measurement. The linear absorption coefficient for Si_3N_4 was 0.69 cm^<-1>, so that the internal stress distributed within specimens less than 5.4 mm thick could be measured by the neutron diffraction method. In order to generate a linear internal stress distribution, a bending moment was applied to a silicon nitride specimen, the thickness of which was 4mm. The incident beam angle and the widths of the incident and diffracted beam slits were adjusted to limit the diffracting area. The distribution of internal stress was measured by scanning the diffracting area from the tensile side to the compressive side. The stress in the diffracting area was determined from the change in the diffraction angle. The measured stress distribution was almost identical to the applied stress distribution. It is concluded that the internal stress of ceramic components can be measured by the neutron diffraction method.
一般社団法人日本機械学会の論文
1996-08-25