The stress–strain behavior of a variety of duplex ceramics was measured with the aid of strain gauges attached to the tensile surface of beams in four‐point flexure. The duplex materials consisted of a matrix of alumina and, alternatively, of yttria–tetragonal‐zirconia composites without (2Y‐TZP) and with alumina (3Y‐TZP20A). Up to 20 vol% pressure zones of different sizes containing unstabilized zirconia were dispersed within the matrices. Different types of stress–strain behavior were distinguished. The results were compared with microcrack and shear band observations of indented andR‐