Kapp, MPa.//2 Kann MPa. m2 4 (, m 0 04 0.2 04 Fis Fig. 7 Fig. 6. Dependence of the apparent fracture toughness on the crack length parameter a in laminate Si3 N4/Si3 N-20 wt. TiN(specimen 1). Areas of compressive layer are shown in grey. Solid curve is the calculated dependence, horizontal line is the fracture toughness of layer material. Dashed line is the tress intensity factor at constant applied stress of crack growth onset. Open circle corresponds to the initial notch, filled circle corresponds to arrested crack. Fig. 7. Dependence of the apparent fracture toughness on the crack length parameter a in laminate Si3N4/Si3N4-20 wt TIN(specimen 2). Designations are the same as in Fig. 6 P N X, Hm Fig 8. Cyclic load -displacement diagram of layered specimen Si3N4/ Si3N-70 wt %TiN with crack. formed during specimen sintering that is probably due to the insufficient strength of these layers. However, propagating crack, fracturing the specimens, did not always pass through channel cracks. It was established specimens of such composition layer cracks did not practically propagate in the direction of loading, and they did not even always start from the tip of a v-notch. As a whole, the fracture pattern of Si3 N4/Si3 N4-70 wt TiN specimens appeared to be very. Therefore, theoretical analysis and calculation of the apparent fracture toughness - crack length dependence of such laminates was not carried out in the present work. To describe crack behavior in layered specimens containing 70% TiN in tensile layer properly, it is necessary to take into account contributions of such factors as crack branching, microcracking, multiple channel cracks formation, crack kinking, etcformed during specimen sintering that is probably due to the insufficient strength of these layers. However, the propagating crack, fracturing the specimens, did not always pass through channel cracks. It was established that specimens of such composition layer cracks did not practically propagate in the direction of loading, and they did not even always start from the tip of a V-notch. As a whole, the fracture pattern of Si3N4/Si3N4–70 wt.% TiN specimens appeared to be very. Therefore, theoretical analysis and calculation of the apparent fracture toughness – crack length dependence of such laminates was not carried out in the present work. To describe crack behavior in layered specimens containing 70% TiN in tensile layer properly, it is necessary to take into account contributions of such factors as crack branching, microcracking, multiple channel cracks formation, crack kinking, etc. 300 Fig. 6 Fig. 7 Fig. 6. Dependence of the apparent fracture toughness on the crack length parameter ~a in laminate Si3N4/Si3N4–20 wt.% TiN (specimen 1). Areas of compressive layer are shown in grey. Solid curve is the calculated dependence, horizontal line is the fracture toughness of layer material. Dashed line is the stress intensity factor at constant applied stress of crack growth onset. Open circle corresponds to the initial notch, filled circle corresponds to arrested crack. Fig. 7. Dependence of the apparent fracture toughness on the crack length parameter ~a in laminate Si3N4/Si3N4–20 wt.% TiN (specimen 2). Designations are the same as in Fig. 6. Fig. 8. Cyclic load – displacement diagram of layered specimen Si3N4/ Si3N4–70 wt.% TiN with crack