セラミックスの研削加工面の評価 : 第2報,表面傷が強度におよぼす影響

概要

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The paper investigates the effects of surface flaws caused by the grinding of zirconia on strength reliability of the material. The following grinding conditions were selected, and grinding operations using a diamond wheel were performed on the tension side of each of five flexural specimens (50mm × 4mm × 3 mm) : (A) creep feed grinding normal to longitudinal direction (grain size ; # 120, depth of cut ; 2 mm, feed ; 30 mm/min), (B) surface grinding after the creep feed grinding (grain size ; # 600, depth of cut ; 4 μm, amount of removal ; 12 μm ) , (C) lapping after surface grinding (amount of removal ; 3.5 to 4.7 μm) , (D) creep feed grdnding in longitudinal direction. For all specimens of (A) and two specimens of (B) , the flaw in the fracture source could qualitatively be detected. The flaws in both (C) and (D) could not be detected. Based on the flaw calibration, the flaw size of (A) was expected to be 12 μm. The crack length at the moment of unstable fracture was longer than the detected crack length. Considering that the crack might extend during loading, the slow crack growth was investigated using a double-torsion specimen. It was demonstrated that the crack had grown to a certain extent during loading since the expected flaw size before loading coincided with the detected value.
社団法人日本機械学会の論文
1993-02-25