Crack Paths 2009

S-N D A T A

Figure 3 presents S-N data plotted against stress amplitude for both values of kt, while

Figure 4 presents equivalent data as a function of the ratio of stress amplitude to yield

strength. It could be argued that the cyclic yield strength should be used, but such data

is available for only two of the alloys the E L CH D G(172 MPa) and the IF (TiNb) G A

(119 MPa).

63.5

19

a)

Radius 38.1

Radius 0.25

30

24

b)

Figure 2. Specimen design for specimens with a) kt=1.0 and b) kt=3.0; m mdimensions.

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E L CH D Gkt = 1 0 %

E L CH D Gkt = 1 1 0 %

I F ( T i N b ) G A k t = 1 0 % F (TiNb) G Ak t = 11 0 % bP) G Ak t =

IF (TiNbP)H D Gk t = 10 % B)G A

S t r e s s A m p li t u d e ( M P a )

a)

104

105

106

107

Fatigue Life (Nf)

Figure 3. a) S-N data given as stress amplitude for kt = 1.

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