GH4169D合金中Pt元素的分配行为及其对强化相γ´稳定性的影响研究

Excellent comprehensive performances, including mechanical property, property stability, resistance to environmental erosion etc, of wrought Ni-bases superalloys, is an urgent and practical requirement to meet the demand of the fifth generation aircraft. Many experiment have proved that noble elements can improve the comprehensive performances of cast Ni-based superalloy while the role of noble elements in wrought Ni-bases superalloys is not yet found. In this case, based on the preliminary results of the applicant and the strong partitioning character of Pt into strengthening phases, the investigations on the partitioning behavior of Pt and the subsequent influence on the stability of strengthening phase γ´ will be carried out by taking the GH4169D superalloy as the model alloy which is selected as the materials for the fourth generation aircraft. The segregating behavior of Pt at interface and the ripening of strengthening phase γ´ will be studied. Besides, the lattice distortion of strengthening phase γ´ and the coherent relationship of γ´/γ will be summarized. Afterwards, on the basis of the microstructural characteristic of the superalloy, the equations of characterizing the diffusion of Pt and the definition of transformation rate equations will be performed. Subsequently, the interrelated dynamic model setup previously by the applicant will be improved. At the same time, the size and quantity of strengthening phase γ´ and the time corresponding to optimizing precipitation quantity will be obtained by numerical simulation. Under these circumstances, the role of Pt will be clarified completely, and the criterion of selecting cheap and alternative element will be provided. The present project will provide experimetal results, therectical basis and quantitative data to the development of alloying, mechanism of stabilizing precipitation and diffusion-induced phase transformation.

研制出力学性能、性能稳定性、环境侵蚀抗力等综合性能优异的镍基变形高温合金，满足我国五代机选材需求，是当前急需解决的工程实际问题。实验已证实，贵金属元素可提高镍基铸造高温合金的综合性能，但尚未有添加到变形合金中的研究结果可借鉴。由此，本项目结合申请人前期研究结果，利用Pt强烈进入强化相的特性，以四代机用变形合金GH4169D为对象，开展Pt的分配行为及其对强化相γ´稳定性影响的研究，掌握Pt相界偏聚行为及γ´相粗化过程，总结γ´相晶格畸变和γ´/γ共格关系的演变规律；然后基于合金微观组织特点，建立表征Pt扩散行为的方程并限定转化速率方程，完善前期建立的动力学关联模型；同时通过模拟计算，获得γ´相尺寸、数量、最佳析出量对应时间等参量的定量结果，掌握Pt的作用机理，形成廉价替代元素的选择依据。研究结果可在合金化方法、析出相稳定化机理、扩散型相变理论发展等方面提供新的实验结果、理论基础和定量数据。

研制出力学性能、性能稳定性、环境侵蚀抗力等综合性能优异的镍基变形高温合金，满足我国五代机选材需求，是当前急需解决的工程实际问题。实验已证实，贵金属元素可提高镍基铸造高温合金的综合性能，但尚未有添加到变形合金中的研究结果可借鉴。由此，本项目结合申请人前期研究结果，利用Pt强烈进入强化相的特性，以四代机用变形合金GH4169D为对象，进行了0Pt-GH4169D和1.5Pt-GH4169D合金的熔炼，研究了其凝固偏析行为和γ´相析出规律的模拟及时效实验；然后研究了变形态合金时效组织稳定性和显微硬度及粗化激活能；此后对元素的分区行为进行了研究，通过对比铸态和变形态GH4169D合金综合分析Pt的机理；最后分析γ´´相在铸态和变形态合金中的析出形式和单侧生长机理及Pt抑制GH4169合金γ´´相粗化的机理，通过对比铸态和变形态GH4169合金综合分析Pt的机理。研究结果可在合金化方法、析出相稳定化机理、扩散型相变理论发展等方面提供新的实验结果、理论基础和定量数据。