常圧,ホットプレスおよびHIP成形したSi₃N₄セラミックスのX線応力測定の基礎

抄録

X-ray elastic constants of sintered, hot-pressed and HIP'ed Si₃N₄ ceramics were determined from various diffraction lines by using CrKα radiation. The measured X-ray elastic constants for (212), (411) and (321) diffraction planes were nearly the same each other and did not depend on the production method. Those for (301) and (210) planes, which were measured in a low diffraction region only for hot-pressed Si₃N₄, were different from those for the above three planes.
Residual stress measurements were tried on the ground surface of hot-pressed Si₃N₄. Mild grinding by a diamond grinding wheel did not produce large residual stress. However, heavy grinding by a SD140 grinding wheel produced a large compressive residual stress state. A non-liner d_ψ-sin²ψ relation was observed in the measurement of (212) plane but no systematic deviation from a straight line could be shown in the both cases of (301) and (201) planes. The lack of ψ-splitting behavior means that the deformation was performed homogeneously in microscopic scale during grinding.