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对涡轮盘用镍基粉末高温合金FGH 4096进行了热模锻造+直接时效处理,探索细化粉末高温合金毛坯组织的工艺及相关增强机制.结果表明:在不降低延伸率的前提下,直接时效处理对于热模锻造后的合金具有明显的强化作用,并且以多方向变形配合直接时效的强化效果最为显著.按多方向热模锻造+直接时效工艺,可使FGH 4096合金的组织显著细化,平均晶粒尺寸达6μm,γ′相析出尺寸达80 nm.OM,SEM和TEM观察表明,除多方向大变形可直接破碎晶粒、细化晶粒外,反复再结晶也是细化晶粒的有效途径;同时,洁净的再结晶晶界完全取代了原始粉末颗粒边界.直接时效处理后保留了多方向变形产生的位错缠结,并且获得更为细小的γ′相.热模锻造+直接时效处理后合金所表现出来的超高强度主要源自于细晶强化、晶界强化、形变强化和γ′相强化的综合作用.
The hot-forging and direct aging treatment of the nickel-base powder superalloy FGH 4096 for the turbine disk were explored to explore the process and the related enhancement mechanism of the refined microstructure of the powder superalloy.The results show that without aging, the direct aging The treatment has obvious strengthening effect on the alloy after hot forging, and the effect of multi-directional deformation and direct aging is the most obvious.According to multi-direction hot-forging + direct aging process, the microstructure of FGH 4096 alloy can be remarkably refined, The average grain size of 6μm, γ ’phase precipitation size of 80 nm.OM, SEM and TEM observations show that, in addition to multi-direction large deformation can directly break the grain, grain refinement, repeated recrystallization is also refined grain Effective way.At the same time, the clean recrystallized grain boundaries completely replace the boundaries of the original powder particles.After the direct aging treatment, the dislocation entanglement caused by the multi-directional deformation is retained and the more fine γ ’phase is obtained. The high strength of the alloy after aging treatment mainly comes from the combined effect of fine grain strengthening, grain boundary strengthening, deformation strengthening and γ ’phase strengthening.