Variation of the Structure of Nickel Alloy Ingots During Heat Treatment.

One of the causes of the low plasticity of nickel-base alloys at high temperatures may be developed dendritic liquation, which causes insufficiently complete dissolution of the hardening phases during heating of the metal prior to deformation. The first quenching of the cast alloy leads to growth of crystal lattice distortions and to hardening of the alloy, which is a distinctive feature of the behavior of the cast alloy in comparison with section metal. The quenching-aging-quenching thermal cycle softens the crystallite bodies and leads to the formation of a fragmented structure.