基于高通量实验的镍基高温合金析出相与晶界协同强化机制研究

Study on the micro-mechanism of strengthening of nickel-based superalloys and their service under high temperature and high pressure can not only enrich and develop the basic theory of alloy strengthening, but also be important for optimizing the processing technology and developing high-performance nickel-based superalloys. By means of combination of theoretical analysis, crystal plasticity finite element, molecular dynamics simulation, high-throughput experiments and microstructural characterization, this project aim to investigate the synergistic effect of multi-scale precipitates and grain boundaries on the strength of nickel-based superalloys. A continuum mechanical model of interaction between dislocation, multi-scale precipitation (micron-scale and nano-scale) and grain boundary will be establish. Based on the high-throughput experimental data and numerical simulation results, the effects of precipitation and grain boundary parameters on the microstructural evolution of nickel-based superalloys will be investigated in order to ascertain the quantitative correlation between precipitation and grain boundary parameters and yield strength, and reveal the micro-mechanism of synergistic strengthening of precipitated phase and grain boundary of nickel-based superalloys. The quantitative correlation between precipitation and grain boundary parameters and high temperature strength of Ni-based superalloy and the main factors affecting its high temperature mechanical properties will be further explored. These researches will provide scientific bases for the design parameters of micro-structure and the optimization of processing technology of high-strength nickel-based superalloy.

镍基高温合金及其高温高压服役环境下的强化微观机理研究可丰富和发展合金强化的基础理论，对于优化制备加工工艺及研发具有高性能镍基高温合金均具有重要的意义。本项目拟采用理论分析、数值模拟、高通量实验相结合的方法，研究镍基高温合金中多尺度析出相与晶界协同作用对材料强度的影响。建立位错、多尺度（微米级和纳米级）析出相与晶界交互作用的连续介质力学模型，结合高通量实验数据和数值模拟结果，分析析出相与晶界的结构特征参数对材料微观组织演变的影响规律，获取镍基高温合金中析出相和晶界微结构参数与材料屈服强度的定量关联，阐明镍基高温合金析出相与晶界协同强化的微观机理。进一步探索镍基高温合金析出相和晶界微结构参数与材料高温强度的定量关联以及影响该合金高温力学性能的主要因素。为加工制备高强镍基高温合金提供细微观结构设计参数和加工工艺参数优化的科学依据。

镍基高温合金及其高温高压服役环境下的强韧化微观机理研究不但可以丰富和发展合金强韧化的基础理论, 而且对于优化制备加工工艺及研发具有高性能镍基高温合金均具有重要的意义。结合理论分析、数值模拟与实验表征，研究了镍基合金拉伸变形过程中位错、析出相、晶粒（晶界）、空隙等微结构演变规律，研究并发掘影响材料强度的微结构几何和分布参数。构建了充分考虑晶粒几何与分布的合金单轴拉伸变形模型，研究了不同晶粒几何与分布下合金的宏观力学响应，并建立镍基高温合金中晶界（晶粒几何与分布）与材料屈服强度的定量关联。评估了材料表面特性、空隙尺寸等对纳米空隙扩张的门槛应力的影响，进一步分析了空隙浓度对合金材料屈服强度的影响规律。基于位错连续模型分析了析出相尺寸与深度对材料表面损伤的影响，进一步探讨了沉淀硬化镍基合金的表面摩擦和磨损行为。实验和模拟相结合研究了选择性激光熔化制造的FeCrNi合金的动态微观结构演变，揭示了温度梯度分布下合金微结构（晶界、析出相、空隙、层错）动态形核与生长机制。这些研究工作可为加工制备高强镍基高温合金提供细微观结构设计参数和加工工艺参数优化的科学依据。