细观非均质性对镍基单晶双相合金塑性行为的影响

Influence of Heterogeneous Microstructure on the Plastic Behavior of Single Crystal Dual Phase Ni-base Superalloy

摘要:

建立了考虑背应力演化和损伤演化的晶体塑性模型，利用所建立的晶体塑性模型研究了应变速率对镍基单晶合金基体相、强化相的影响。结果表明，镍基单晶基体相和强化相均表现出明显的率相关性。单晶双相合金的细观非均质性导致非均匀的微观应力和微观塑性滑移。塑性滑移变形首先发源于基体相。微观应力和塑性滑移的非均匀性可能是材料微观损伤积累和孔洞形核的根源。

Abstract:

A theory of crystal plasticity including back stress and damage evolutions has been established in this paper. The effects of strain rate on the matrix and precipitate phases of Ni-base superalloy have been analyzed using the theory. The computational result revealed that the both matrix and precipitate phases were seriously affected by strain rate. The nonuniform microcosmic stresses and plastic slips were induced by the microcosmic heterogeneity of single crystal dual phase alloy. The microcosmic plastic slips originate in matrix firstly. The heterogeneity of microcosmic stresses and plastic slips is probably the origin of the damage evolution and the nucleation of micro voids.