On the mechanism of fatigue crack growth in silicon nitride

Ceramics and ceramic coatings in orthopaedics

“…10(b) is a representative microstructure of these types of Al 2 O 3 -ZrO 2 nano-composites. For reference purposes, fatigue testing has been conducted for most of the biomaterials of Table 1a, and the reader is referred to selected publications for Al 2 O 3 [357][358][359][360][361][362], Mg-PSZ [363][364][365], Ce-TZP [366,367], Y-TZP [346,[368][369][370], Ce-and Y-ZTA [212,348,355,371,372], ATZ [211], Si 3 N 4 [344,354,373,374], CoCr [375], Ti6Al4V [376,377], PEEK [378][379][380], and cortical bone [381][382][383].…”

Effect of Grain‐Boundary Phase on Dynamic Compression Fatigue in Hot‐Pressed Silicon Nitride

“…4 It was concluded that enhanced crack growth rates in air are caused by stress corrosion cracking. In view of the results of Okazaki et al, 4 the effect of the long delay between two successive dynamic cycles on the fatigue life of silicon nitride was evaluated. Quasi-static tests were performed on CBP silicon nitride at a strain rate of 0.01/s with a gap of approximately 4 min between two cycles.…”

“…Different types of fatigue tests, such as four-point bending tests, [1][2][3][4][5] cantilever bending tests, 6,7 rotating bending tests, 8 and compression-tension tests, 9 have been conducted on silicon nitride. The effects of compression stress on the fatigue life in four-point bending tests was studied by Nikkila and Mantyla.…”

“…In some of these experiments, the fatigue lives of two identical samples tested under similar conditions differed by as much as a factor of 10, 1 and in another study 7 they differed by as much as 10 3 times. Fatigue crack growth, for silicon nitride fluxed with yttria and alumina, under vacuum in four-point bending tests was studied by Okazaki et al 4 Their results indicated that it is possible to propagate fatigue cracks in silicon nitride under vacuum. Higher crack growth rates were observed when the material was tested in air compared to vacuum, suggesting that stress-corrosion cracking plays an important role in the fatigue crack growth in silicon nitride, but it alone cannot account for the observed crack growth rates.…”

Fatigue Crack Growth Behavior of Silicon Nitride: Roles of Grain Aspect Ratio and Intergranular Film Composition

“…Rather, higher loading ratios are thought to decrease the sliding distance and reduce the wear on frictional bridges thus giving slower crack growth at a given K max . Silicon nitrides are also sensitive to moisture in the environment which causes increased crack growth rates; however, in dry environments crack growth still occurs but at a much lower rate …”