EFFECT OF SINGLE-CRYSTAL BILLET MACRO- AND MICROSTRUCTURE ON INTERMETALLIC ALLOY STATIC AND DYNAMIC STRENGTH

Research is presented for the effect of macro- and microstructure of single-crystal billets of intermetallic alloy VKNA-25 with different crystallographic orientations , , and , prepared by directional crystallization using a seed, on material static an dynamic strength. The effect of microstructure on short- and long-term strength at 900, 1000, 1100, 1200°C on bases of 10, 100, 500, and 1000 h, and low-cycle fatigue (LCF) resistance by a “stiff” cycle, is studied. LCF tests are performed under cyclic tension conditions with a cycle asymmetry coefficient R = 0 at 850 and 1000°C. The dependence of stress rupture strength and LCF on single-crystal billet macro- and microstructure and test temperature is established.