Publication result detail

ON THE RELATION BETWEEN DENDRITE MICROHETEROGENEITY INDEX AND EFFECTIVE PARTITION COEFFICIENT OF ELEMENTS IN CREEP-RESISTING Ni-ALLOY BLADES

DOBROVSKÁ, V., DOBROVSKÁ, J., PODRÁBSKÝ, T., STRÁNSKÝ, K.

Original Title

ON THE RELATION BETWEEN DENDRITE MICROHETEROGENEITY INDEX AND EFFECTIVE PARTITION COEFFICIENT OF ELEMENTS IN CREEP-RESISTING Ni-ALLOY BLADES

English Title

ON THE RELATION BETWEEN DENDRITE MICROHETEROGENEITY INDEX AND EFFECTIVE PARTITION COEFFICIENT OF ELEMENTS IN CREEP-RESISTING Ni-ALLOY BLADES

Type

Peer-reviewed article not indexed in WoS or Scopus

Original Abstract

The chemical microheterogeneity of elements in two cast blades of the first stage of a gas turbine was measured. The first blade was measured in as-cast state, the second one after operation. By means of an original method, the microheterogeneity indíces IH and the effective partition coefficients kef were established. Using a metallographic method, the interdendritic distances, 2L = 32,8 mikro m, of the creep-resisting nickel-alloy blades were measured. By means of the Brody-Flemings (BF) heterogeneity model and with the help of mathematical and statistical methods, a relation between the parameters IH and kef and parameter a = D /L2 of the BF model has been derived. Then the numerical values of parameter alfa from measured heterogeneity data (IH and kef) were calculated and a comparíson was made with literature data. By means of numerical values of parameter alfa it was possible: - to evaluate the relations among diffusion coefftcients D of element of nickel-based alloy (these elements can segregate eitlier in the liquid or in the solid state); - to appreciate the local solidification time 9~, - and to compare the parameters of as-cast and operated blades.

English abstract

The chemical microheterogeneity of elements in two cast blades of the first stage of a gas turbine was measured. The first blade was measured in as-cast state, the second one after operation. By means of an original method, the microheterogeneity indíces IH and the effective partition coefficients kef were established. Using a metallographic method, the interdendritic distances, 2L = 32,8 mikro m, of the creep-resisting nickel-alloy blades were measured. By means of the Brody-Flemings (BF) heterogeneity model and with the help of mathematical and statistical methods, a relation between the parameters IH and kef and parameter a = D /L2 of the BF model has been derived. Then the numerical values of parameter alfa from measured heterogeneity data (IH and kef) were calculated and a comparíson was made with literature data. By means of numerical values of parameter alfa it was possible: - to evaluate the relations among diffusion coefftcients D of element of nickel-based alloy (these elements can segregate eitlier in the liquid or in the solid state); - to appreciate the local solidification time 9~, - and to compare the parameters of as-cast and operated blades.

Key words in English

microheterogeneity, partition coefficient, Ni-based alloy

Authors

DOBROVSKÁ, V., DOBROVSKÁ, J., PODRÁBSKÝ, T., STRÁNSKÝ, K.

Released

01.04.2001

ISBN

1335-1532

Periodical

Acta Metallurgica Slovaca

Volume

7

Number

1/2001

State

Slovak Republic

Pages from

56

Pages count

5

BibTex

@article{BUT40296,
  author="Věra {Dobrovská} and Jana {Dobrovská} and Tomáš {Podrábský} and Karel {Stránský}",
  title="ON THE RELATION BETWEEN DENDRITE MICROHETEROGENEITY INDEX AND EFFECTIVE PARTITION COEFFICIENT OF ELEMENTS IN CREEP-RESISTING Ni-ALLOY BLADES",
  journal="Acta Metallurgica Slovaca",
  year="2001",
  volume="7",
  number="1/2001",
  pages="5",
  issn="1335-1532"
}