摘要
The effects of varying strain rates and deformation temperatures on the microstructure evolution of the FGH4113A alloy were investigated through hot compression experiments.During hot deformation,grain evolution is primarily governed by dynamic recrystallization(DRX)and twinning primarily.Furthermore,the pinning effect of the primaryγ'phase(γ'p phase)plays a crucial role in grain refinement.Lower strain rates or higher temperatures facilitate DRX,twinning,and the dissolution of theγ'p phase.At 1140℃,significant dissolution of theγ'p phase and the subsequent loss of its pinning effect reduce twinning activity.A unique twinning mechanism,termed“pinning twinning”,is identified,occurring exclusively under the influence of the pinning effect.When grain boundary migration fails to accommodate dislocations due to the pinning effect,grains preferentially eliminate dislocations via twinning,thereby reducing local strain energy.The grain size prediction model is improved by considering the pinning effect.
通过热压缩实验探讨了不同应变速率和变形温度对FGH4113A合金显微组织演变的影响。在热压缩变形过程中,动态再结晶和孪生是晶粒组织演变的主要方式,一次γ′相(γ'p相)的钉扎作用则是细化晶粒的主要手段。降低应变速率或升高变形温度会促进动态再结晶和孪生的发生,以及γ'p相的溶解。当变形温度为1140℃时,γ'p相的大量溶解及钉扎作用失效导致孪生减弱。发现了一种仅在钉扎作用下出现的孪生机制,即“钉扎孪生”。当位错由于γ'p相对晶界的钉扎作用无法通过晶界迁移消耗时,晶粒优先通过孪生来消除位错,以降低局部应变能。建立了考虑钉扎作用的晶粒尺寸预测模型。
基金
supported by the National Key Research and Development Program of China(No.2022YFB3706902)
Innovation Project for Graduate Students of Hunan Province
China(No.1053320212786)
supported in part by the High Performance Computing Center of Central South University,China。
