镍基变形高温合金热塑性微体积成形机理及性能控制

The aircraft and guided weapon system in aerospace field tend to the development of miniaturization, making the machining feature size of micro-engine hot end components substantially reduce meso scale. The micro component manufacture of nickel-base wrought superalloys becomes the key problem. The project will study thermoplastic micro-volume deformation behavior of nickel-based wrought superalloy. The effects of sample size, grain size and strengthening phase content on flow stress in the process of thermoplastic micro-deformation will be analyzed. The coupling mechanism about the strengthen effect of strengthening phase on flow stress and the pinning effect of strengthening phase on grain will be indicated. Thermoplastic micro-deformation theory model about the effect of strengthening phase on grain boundary migration will be built based on mesoscopic dislocation theory. The influence mechanism of strengthening phase on scale effects will be revealed and microstructure evolution pattern will be further studied in the process of thermoplastic micro-deformation for nickel-base wrought superalloys. The defect forms and formation mechanism for thermal deformation will be discussed. Forming process stability and the issue of performance control will be resolved and controllable manufacturing of micro-volume components for nickel-base superalloy will be realized. Researches for this project will not only break through forming key technique for the micro component manufacture of nickel-base wrought superalloys, but also facilitate the practical application of plastic micro-forming technology in micro-fabrication field.

航空航天领域飞行器及制导武器系统趋向于微型化发展，使得微型发动机热端部件的加工特征尺寸大幅减小至介观尺度，镍基变形高温合金微型构件制造是关键问题。本项目研究镍基变形高温合金热塑性微体积变形行为，分析试样尺寸、晶粒尺寸和强化相对热塑性微变形过程中流变应力的相互影响，明晰强化相对流变应力强化作用和对晶粒钉扎作用的耦合机制，基于介观尺度位错理论建立强化相对晶界迁移影响的热塑性微变形理论模型，揭示镍基变形高温合金热塑性微变形过程中强化相对尺度效应的影响机理，进一步研究镍基变形高温合金热塑性微变形过程的组织演化规律，探讨热变形缺陷形式与形成机制，解决成形工艺稳定性和性能控制问题，实现镍基变形高温合金微型体积构件的可控制造。本项目的研究不仅能够突破镍基变形高温合金微型构件成形关键技术，并且可以促进塑性微成形技术在微制造领域的实际应用。

本项目针对镍基变形高温合金微型构件制造中关键问题-介观尺度塑性变形尺度效应开展了系统的研究，通过固溶处理和时效处理获得了不同晶粒尺寸和析出相的微观组织，分析了晶粒尺寸、试样尺寸与晶粒尺寸之比（D/d）和析出相等对微型圆柱单向压缩流变应力的影响，发现当D/d≥9.7时，流动应力与晶粒尺寸之间满足Hall-Petch关系，当D/d<9.7时，微压缩时流动应力偏离了Hall-Petch关系，出现了流动应力尺度效应现象。考虑微型圆柱单向压缩过程中难变形区、小变形区和大变形区3个压缩应变分区，引入晶界因子、Taylor因子等参数，构建了介观尺度流动应力尺度效应理论模型；发现在相同晶粒尺寸下，随着δ相含量的增加，材料流动应力增大，明晰了强化相对流变应力强化作用和对晶粒钉扎作用的耦合机制，考虑基体、溶质原子、沉淀相贡献的流动应力，基于介观尺度位错理论建立了强化相对尺度效应影响的多相材料本构模型，揭示了镍基变形高温合金塑性微变形过程中强化相对尺度效应的影响机理；研究了镍基变形高温合金微型圆柱单向压缩过程的组织演化规律，分析晶粒尺寸、试样尺寸与晶粒尺寸之比以及δ相对非均匀变形行为的影响规律，基于介观尺度晶体塑性理论实现了微观组织演化的实时可视化，提供了一种精确揭示介观尺度下微压缩过程微观组织演化机理的手段，解决了成形工艺稳定性和性能控制问题，为镍基变形高温合金微型体积构件的可控制造提供理论基础。本项目的研究成果促进了镍基变形高温合金塑性微成形技术在微制造领域的广泛应用，具有重要的理论意义和实际应用价值。

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