HIGH TEMPERATURE BRITTLENESS OF CAST ALLOYS

Анотація

Over-all mechanical properties of alloys are extremely low at the last stage of solidification where alloy exists at brittle temperature range (BTR). When the solidification process is completed a sudden and marked change in strength and ductility of metal is observed. It means that as long as liquid phase is present, metal will fail in a brittle manner. There are known different theories of brittleness of alloys in existence of liquid phase. The idea involved by authors of the paper is as follows: three major factors caused by presence of liquid may be taken into account:

       – decreasing the energy needed for crack nucleation;

      – increasing atomic diffusional flux out of the crack tip;

      – creating a path for abnormally quick diffusion of atoms from the crack tip.