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自行设计开发了适合工业化生产高纯净,低偏析,无宏观缺陷铸锭的电渣重熔连续定向凝固技术(ESR-CDS)的设备和工艺,利用该技术成功制备了直径为150mm的René88DT合金定向凝固铸锭。采用XRD测试了定向凝固柱状晶的生长取向,结果表明,ESR-CDS René88DT铸锭柱状晶择优生长方向为<100>系晶向;ESR-CDS铸锭与传统ESR铸锭相比,枝晶组织生长方向保持一致,二次枝晶臂均匀细小,元素偏析程度低,且晶间一次析出相呈颗粒状,尺寸细小;等温热压缩实验结果表明,ESR-CDS René88DT合金热压缩试样在1100℃,0.05~0.1 s-1应变速率下可达到70%以上压缩变形量并获得均匀细小的动态再结晶组织;ESR-CDS René88DT合金铸锭经等温锻造制备出了170mm×73mm的饼坯件,锻压变形量超过70%,饼坯件除上下两端的变形死区外均发生了动态再结晶,晶粒尺寸约50μm。
The equipment and technology of electroslag remelting continuous directional solidification (ESR-CDS) for industrial production of high purity, low segregation and non-macro-defect ingots have been designed and developed by ourselves. The René 88DT alloy with the diameter of 150 mm Directional solidification ingot. The growth orientation of the solidified columnar crystals was measured by XRD. The results show that the preferred growth direction of columnar grains of ESR-CDS René88DT ingot is the <100> system orientation. Compared with the traditional ESR ingot, the dendritic structure The growth direction is consistent, the secondary dendritic arm is uniform and small, the degree of elemental segregation is low, and the primary precipitation phase is grainy and small in size. The isothermal hot compression test results show that the heat-compression sample of ESR-CDS René88DT alloy has a grain size of 1100 ℃, 0.05 ~ 0.1 s-1 strain rate can reach more than 70% of the compressive deformation and to obtain uniform and fine dynamic recrystallization microstructure; ESR-CDS René88DT alloy ingot isothermal forging prepared 饼 170mm × 73mm cake blanks , Forging deformation of more than 70%, cake blank in addition to the deformation of the upper and lower ends of the dead zone occurred within the dynamic recrystallization, the grain size of about 50μm.