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通过水冷铜坩埚熔炼吸铸制备了不同直径的GH4169高温合金圆柱试样,采用金相显微镜(OM)和扫描电子显微镜(SEM)及X射线衍射(XRD)等对其凝固组织和析出相进行了分析,研究冷却速率对GH4169合金铸态组织和力学性能的影响规律。结果表明,随着冷却速率的增加,合金二次枝晶臂间距减小,凝固枝晶组织明显细化;Laves相尺寸减小且呈现弥散分布;Nb和Mo元素的偏析减轻;合金硬度和强度提高。
Cylindrical samples of superalloy GH4169 with different diameters were prepared by smelting in a water-cooled copper crucible. The solidification microstructure and precipitation phase were characterized by OM, SEM and XRD. The influence of cooling rate on the as-cast microstructure and mechanical properties of GH4169 alloy was analyzed and studied. The results show that with the increase of cooling rate, the interdendritic arm spacing decreases and the dendritic structure is refined obviously. The Laves phase size decreases and disperses, the segregation of Nb and Mo elements decreases. The hardness and strength improve.