Investigation of the stress rupture behavior of GTD-111 superalloy melted by VIM/VAR

摘要: The effects of vacuum induction melting (VIM) and arc remelting (VAR) processes on the microstructure stress rupture properties Ni-based GTD-111 superalloy were investigated. Samples master alloy melted in VIM VAR furnaces then poured into a preheated ceramic mold for melt or water-cooled copper melt. as-cast samples examined radiographically to ensure that no casting defects present final castings; heat-treated using standard heat-treatment cycle. was investigated optical microscopy scanning electron conjunction with energy-dispersive X-ray spectroscopy microanalysis. On basis ASTM-E139, tests carried out at 1000°C under 300 MPa. results showed γ matrix, fine γ′ precipitates, γ–γ′ eutectic structure, carbide particles, some harmful phases such as σ η samples. precipitates cubic morphology appeared matrix after process. extent segregation amount structure formed VAR-prepared sample less than VIM-prepared sample. time 43% longer