Characteristics of inclusions and precipitation phase distribution in large size GH4742 superalloy ingot
TIAN Qiang1, YANG Shu-lei2, QIN He-yong1, YANG Shu-feng2, WANG Ning2, HAO Yong-zhou1
1. Department of High-Temperature Materials, Central Iron and Steel Research Institute, Beijing 100081, China;
2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
In order to clarify the distribution characteristics of precipitated phases and inclusions in the ingot organization of large size GH4742 alloy, the composition, morphology and quantity of inclusions and precipitated phases in 660 mm ingots of GH4742 alloy were analyzed by electron scanning microscopy, metallographic analysis and electrolytic corrosion. The results showed that the inclusions in alloy ingot mainly consisted of SiO2, CaO, Al2O3-SiO2, CaO-SiO2 and carbonitrides. The number of inclusions in alloy ranged from 14.7 to 85.8 inclusions/mm2, and inclusions were present in clusters at a radius of 1/4 from the center of ingot. A large number of γ′ phase, (γ+γ′) eutectic phase, δ phase, μ phase, Laves phase, carbide phase and boride phase were distributed in the alloy ingot, and their distribution and morphology were significantly different between dendrites and dendrites as well as in the center and edges of ingot.
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2022, Vol. 32 
