A GENERIC MICROSTRUCTURE-EXPLICIT MODEL OF CREEP IN NICKEL-BASE SUPERALLOYS
A GENERIC MICROSTRUCTURE-EXPLICIT MODEL OF CREEP IN NICKEL-BASE SUPERALLOYS
复制标题
镍基高温合金蠕变的通用显微组织模型
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
M. Mclean
中科院分区：
文献类型：
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作者：
H. Basoalto;S. Sondhi;B. Dyson;M. Mclean
过去模拟工程合金蠕变行为的方法要么完全是经验的，要么具有与当前对变形和断裂机制的理解一致的函数形式，通过与现有的蠕变数据库进行比较而得到校准。它们没有具体包括对被认为赋予合金蠕变抗力的微观结构特征的量化测量。本文回顾和推广了颗粒强化合金的微观组织蠕变模型，模型参数直接关系到镍基高温合金微观组织的可测量特性。该模型解释了高温合金蠕变过程中发生的三种组织变化：(I)JC析出物的粗化；(Ii)可移动位错密度随累积蠕变应变的逐渐增加；(Iii)晶界空洞的发展。将使用一组具有特定合金微结构的商业合金来展示每种合金的相对优势。需要强调的是，模型生成的曲线是使用输入微观结构特征的真实预测，并不符合蠕变数据的经验。
Past approaches to modelling the creep behaviour of engineering alloys have been either totally empirical or, while having functional forms consistent with current understanding of deformation and fracture mechanisms, have been calibrated by comparison with an available creep database. They have not specifically included quantitative measures of the microstructural features that are thought to impart creep resistance to the alloys. The present paper reviews and extends a microstructure-specific model of creep in particle-strengthened alloys in which the model parameters are directly related to measurable characteristics of the microstructure of nickel-base superalloys. The model accounts for three previously identified changes in microstructure that occur during the creep of superalloys: (i) coarsening of the Jc precipitate; (ii) the progressive increase in mobile dislocation density with accumulated creep strain; and (iii) the development of grain boundary cavities. The relative dominance of each will be demonstrated using a set of commercial alloys with specific alloy microstructures. It is emphasised that the model-generated curves are true predictions using input microstructural characteristics and are not empirically fitted to the creep data.