| Autor: |
Cieslak, M., Knorovsky, G., Headley, T., Romig, A. |
| Zdroj: |
Metallurgical transactions. Part A: Physical Metallurgy & Materials Science; 1986, Vol. 17 Issue 12, p2107-2116, 10p |
| Abstrakt: |
The weld metal microstructures of five commercial nickel base alloys (HASTELLOYS* C-4, C-22, and C-276, and INCONELS* 625 and 718) have been examined by electron probe microanalysis and analytical electron microscopy. It has been found that solidification terminates in many of these alloys with the formation of a constituent containing a topologically-close-packed (TCP) intermetallic phase (i.e., σ, P, Laves). Electron microprobe examination of gas-tungsten-arc welds revealed a solidification segregation pattern of Ni depletion and solute enrichment in interdendritic volumes. New PHACOMP calculations performed on these segregation profiles revealed a pattern of increasing M (metal- d levels) in traversing from a dendrite core to an adjacent interdendritic volume. In alloys forming a terminal solidification TCP constituent, the calculated M values in interdendritic regions were greater than the critical M values for formation of σ as stated by Morinaga et al. Implications of the correlation between TCP phase formation and M in the prediction of weld metal solidification microstructure, prediction of potential hot-cracking behavior, and applications in future alloy design endeavors are discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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