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The forming process and mechanism of the reaction of Ti–6Al–4V investment casting made by Zr(CH_3COO)_2-Y_2O_3 shell in vacuum casting was studied.Statistic was manipulated to study the distributions and types of the reaction layers. The morphology and composition of the reaction layers were tested using field emission scanning electron microscopy(FESEM) combined with energy-dispersive spectroscopy(EDS). Phase of the reaction layers was characterized by X-ray diffraction(XRD).Composition of the shell reaction zone was measured by X-ray fluorescence(XRF) method. The results suggest the reaction contains oxidation and element evaporation, and the melt reacts little with the shell but mainly with the remnant gas. The reaction layers contain three types due to different forming stages: the titanium oxidation film, the concretion film and the shell reaction zone. The interfacial temperature and pressure affect the reaction mechanism and degree, leading to three types of concretion films that differ in thickness, content and color.
The forming process and mechanism of the reaction of Ti-6Al-4V investment casting made by Zr (CH_3COO) _2-Y_2O_3 shell in vacuum casting was studied. Statistic was manipulated to study the distributions and types of the reaction layers. The morphology and composition of the reaction layers were tested using field emission scanning electron microscopy (FESEM) combined with energy-dispersive spectroscopy (EDS). Phase of the reaction layers was characterized by X-ray diffraction (XRD) X-ray fluorescence (XRF) method. The results suggest the reaction contains oxidation and element evaporation, and the melt reacts little with the shell but mainly with the remnant gas. The reaction layers contain three types due to different forming stages: the titanium oxidation film, the concretion film and the shell reaction zone. The interfacial temperature and pressure affect the reaction mechanism and degree, leading to three types of concretion films that differ in thickness, content and color.