2及び4mol%イットリア添加正方晶ジルコニアの疲労(第2報)

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The fatigue behavior of tetragonal zirconia polycrystals (Y-TZP) containing 2 and 4 mol% Y_2O_3 was studied by measuring their fracture strength as a function of stressing rate (dynamic fatigue technique) . The average grain sizes of 2 and 4 mol% Y_2O_3-TZP were 0.46 and 0.56 μm, respectively. Stress-displacement relationships except Z 2 Y-I at the crosshead speed of 0.005 mm/min at 250℃ showed elastic behavior, while that of Z 2 Y-I at the crosshead speed of O. 005 mm/ min at 250℃ showed inelastic behavior. The crack growth parameter N of Z 2 Y-I was 104 at 20℃ and 21.9 at 250℃. The N value of Z 4 Y-I was 32.3 at 250℃. The N values at 20℃ decreased with increasing Y_2O_3 content from 2 to 4 mol%, but were larger than 40 indicating little fatigue. The N values in the grain size group of more than I ,μm at 250℃ were less than 10 indicating remarkable fatigue. The N values in the grain size group of 0.5 μm showed a maximum at 3 mol% Y_2O_3, and decreased with decreasing Y_2O_3 content from 3 to 2 mol% or with increasing Y_2O_3 content from 3 to 4 mol% The monoclinic zirconia content on the fracture surface decreased monotonously with increasing Y_2O_3 content for a certain grain size, while that for a certain Y_2O_3 content increased with increasing grain sizes.
社団法人日本セラミックス協会の論文
1988-07-01