摘要镍基高温合金具有良好的韧性，抗热腐蚀性能和抗氧化性能十分优异，并且 其在高温状态下具有非常优秀的抗疲劳性，因此镍基高温合金在航空、航天等领 域中具有非常广泛的应用。镍铝高温合金强化相（γ′ 相）的尺寸、组织形态、体 积分数和空间等的分布状况对合金的强化程度有着重要的影响。因此，对于 γ′ 相 的微观组织以及粗化行为的研究在提高镍铝高温合金性能方面有着非常重要的作 用。68527
本文利用相场方法和微观弹性理论、采用半隐式傅里叶谱算法和周期性边界 条件，在傅里叶空间中对 Ginzburg Landau 方程和 Cahn Hilliara 方程进行数值 求解。利用 Matlab7.0 编程，研究了弹性应力下不同的 Al 浓度对 Ni Al 合金 γ′ 相 的沉淀过程中微观组织演化的影响规律。
随着合金中 Al 浓度的不断上升， Ni Al 合金 γ′ 相的微观形貌由最初低浓度 时的长条状和块状混合组织的分布逐渐转变为高浓度时的长条状分布，其体积分 数增加，成分和序参数变化速率增大，但是其粗化的速率会随着 Al 浓度的不断增 加反而会逐渐减小。
毕业论文关键词 Ni Al 高温合金，沉淀，相场，微观组织，浓度
Title Phase-field impact studies on nickel-aluminum aluminum concentration superalloy microstructure evolution
Abstract
Nickel-based super-alloys have good toughness, heat resistance , oxidation resistance and excellent fatigue resistance at high temperatures, which results in their wide use in the aviation, aerospace and other fields. Because the size distribution, morphology, and volume fraction of the space of the phase (γ 'phase) have an important influence on the degree of strengthening of the alloys, the study of the microstructure and coarsening behavior of γ 'phase becomes so important in improving the performance of high-temperature nickel-aluminum alloys.
Based on the Phase-field model, by using the periodic boundary conditions, Ginzburg-Landau and Cahn-Hilliard kinetic equation is solved with a semi-implicit fourier-spectral method. With Matlab7.0 programming, We investigated the influence of elastic stress different Al concentrations Ni-Al alloy γ 'phase precipitation during the evolution of microstructure.
As the concentration of Al alloys rises ,the morphology of γ 'phase of Ni-Al alloys which is mixtures of strip-typed and massive organization at low concentrations in the beginning, gradually transformed into a long strip-typed distribution at high concentrations ,during which,the composition, volume fraction and the rate of the order parameter's changing increase, with decreasing coarsening rate.
Keywords Ni-Al alloys, Precipitation, Phase-field, Microstructure, Concentration
目次
1 绪论 1
1.1课题研究背景及意义 1
1.2材料的模拟和研究 1
1.3相场法的提出及其特点和发展 2
1.4镍基高温合金的强化机理 5
1.5本文研究的内容 5
2 相场模型 7
2.1相场法模型的基本理论基础 7
2.2 相场模型 相场法研究铝浓度对镍铝高温合金微观组织演化的影响:http://www.751com.cn/cailiao/lunwen_77092.html