Issue34

Y. Nakai et alii, Frattura ed Integrità Strutturale, 34 (2014) 246-254; DOI: 10.3221/IGF-ESIS.34.26

(B)

(A)

Rolling direction

Observation direction

(A)

Rolling direction

Contact ball

■ Crack

y

y

y

(B)

z

x

x

z

(C)

Contact surface 50 m 

(C)

x

Inclusions

z

(a) N = 1.100 × 10 7 cycles

(B)

(A)

(B)

(A)

y

y

y

■ Crack

y

z

z

x

x

(C)

(C)

■ Flaking

50 m 

50 m 

x

x

z

z

(b) N = 1.168 × 10 7 cycles

(c) N f

= 1.295 × 10 7 cycles

Figure 6 : 3D-images of crack and inclusion.

Figure 7 : SEM micrograph of surface crack ( p max

= 5.39 GPa, N = 6.00×10 6 cycles).

250