PSI - Issue 7

L.L. Liu et al. / Procedia Structural Integrity 7 (2017) 174–181

177

4

L. L. Liu et al. / Structural Integrity Procedia 00 (2017) 000–000

method is used to obtain the relationship between the test lifetime and the δ phase content as shown in Fig.3 (b). It can be seen that the low cycle fatigue lifetime of GH4169 specimens is highly correlated with the grain size, but irrelevant with the content of the δ phase, which is consistent with the conclusion in [16]. Combined with experimental data, a negative correlation between the grain size and LCF lifetime is found induced by the grain refinement strengthening theory. (a)

(b)

(c)

(d)

Fig. 2 Optical microscope images of the grain structures sampled at (a) ε max =1.0%, (b) ε max =0.9%, (c) ε max =0.8%, (d) ε max =0.7%.