The study consisted in assessing the influence of surface and volume modification on the characteristics of high-temperature creep of

castings made of waste products of nickel-based superalloys IN 713C and the MAR-247. The results of high-temperature creep tests

performed under conditions of two variants of research were analysed. The characteristics of creep according to variant I were obtained on

the basis of earlier studies of these alloys with the parameters T=982o

C, σ=150MPa [1]. Variant II included carrying out creep tests of

alloy IN713C with the parameters T=760o

C, σ =400MPa and alloy MAR247 with the parameters: T=982o

C, σ=200MPa.Developed creep

characteristics were compared with the results of these alloys with the parameters according to variant I of the study. It was observed that

the conditions of experiments carried out depending upon the value of the creep test temperature and stress with the creep stability depends

on the size of the macrograin (I variant of the studies) or such influence was not observed (II variant of the studies). Stability of samples

with coarse structure in variant I of creep tests was significantly higher than the samples with fragmented grain. It was found that the

observed stability conditions are dependent on the dominant deformation mechanisms under creep tests carried out - diffusion mechanism

in variant I and a dislocation mechanism in variant II of the study. The conditions for the formation and growth of the cracks in the tested

materials, including the morphological characteristics of their macro-and microstructure were tested.