Fig. 1 Schematic illustration of the creep test sample

Fig. 2 Creep curve of PWA 1483 at 980 °C/220 Mpa

Fig. 3 Evolution of the number and volume fraction of micro-pores during creep at 980 °C/220 Mpa

Fig. 4 Tomography revealing the evolution of micro-pore distribution during creep: a-d top views of the gauge section, and e-h cross sections parallel to the applied stress. a, e 0 h, b, f 90 h, c, g 111 h, d, h 115 h

Fig. 5 Statistical histograms of the evolution of the small, medium and large-sized pores during creep: a size distribution of pores, and b average growth rates of pores. The growth rate v is calculated as: v?=?(Di-Di-1)/(ti-ti-1), where Di is the average diameter of micro-pores at interrupted time i (ti)

Fig. 6 Evolution of shape factor of micro-pores during creep

Fig. 7 3D morphological evolution of representative a Small, b Medium, c and d Large pores at creep time of 0 h, 70 h, 101 h, 113 h, and 115 h, respectively. Numbers in brackets indicate Deq (μm) of the pores

Fig. 8 3D morphologies showing the formation of a large pore during creep: a 0 h, b 111 h, c 113 h, d 115 h. Numbers in brackets indicate Deq (μm) of the pores

Fig. 9 3D characteristics of the sample, a-d after 115 h creep and e-h at the rupture time, 115.16 h. a and e 3D macroscopic views, b and f top-view projections, c and g front-view tomograms of the gauge section along dashed line 1 in b, d and h front-view tomograms of the gauge section along dashed line 2 in b

Fig. 10 Variation of the creep strain and the volume fraction of pores during creep at 980 °C/220 MPa

Fig. 11 Comparison of the creep strain rate and the average growth rate v of three type pores during creep at 980 °C/220 MPa

Fig. 12 Distribution of three large pores in the gauge section after 115 h creep