Metallography-microprobe method was used to study the influence of P, S, B and Si on the solidification process and segregation of GH169 alloy. It was found that even at very low levels, these trace elements still profoundly imposed effect on the solidification segregation of this alloy, The mechanism is that these elements have a very limited solubility in δ solid solution and greatly enrich in the front area of the solidification interface. Because of lack of the formation of high melting point compounds, their enrichment can reach very high level at the late stage of solidification and make the solubility of Nb in the δ solid solution lower, resulting in the increase of Nb amount in remaining liquid. Different from other Ti-high superalloys, lower Ti content in GH169 alloy makes the precipitation temperature of Y phase very low, so S appear obvious promotion effect of segregation. According to this results, a low segregation GH169 alloy can be obtained by controlling P < 0.001%, S < 0.05% and B taking the lower limit on the specification and good results was acquired on industrial ingot scale that not only its segregation was greatly decreased, but also the stress rupture property was significantly raised because of the purification of boundaries. It is first discovered that there is liquid-precipitated δ phase in GH169 alloy. P, S, B and Si have a obvious effect on its formation. Among them, Si appears largest influence and high Si content prevents its formation; high P, S and B contents also make it difficult to form.
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