R-Curve Behaviour of Alumina Matrix Ceramics with Long Cracks
The R-curve (KR versus crack length c) behavior has been examined in alumina-10 wt% zirconia ceramics with 3 mol% yttria stabilized zirconia, alumina-10 wt% zirconia ceramics with 12 mol% nano ceria stabilized zirconia and Al2O3-30 wt% Ti(C,N) ceramics. An observation of in situ microscopic long-through thickness crack growth during three point bending (3PB) of a single edge notched beam (SENB) enabled measurement of the R-curve. It was found that both aluminazirconia ceramics with yttria or ceria stabilized zirconia exhibit a rising R-curve while for Al2O3-30 wt% Ti(C,N) ceramics such relationship was not observed. Moreover the slow crack growth parameters (n, logA) were determined by means of load-relaxation technique for tested alumina matrix ceramics.
M. Szutkowska et al., "R-Curve Behaviour of Alumina Matrix Ceramics with Long Cracks ", Advances in Science and Technology, Vol. 45, pp. 1652-1657, 2006