An Experimental and Modelling study of the Evolution of Inelastic Strain and its Implications to Re-crystallisation in Single Crystal Turbine Blades

该项目的总体目标是开发一种在极端温度条件下γ素增强高温合金蠕变的微结构敏感本构描述。感兴趣的温度范围将在1300℃至1150℃之间，具体考虑到涡轮叶片在后续热处理过程中的再结晶。这项工作将包括确定主要的变形机制，并了解在感兴趣的条件下的微观结构，特别是通过使用微偏析长度尺度的小规格体积的微型测试。从这些信息中，有望推导出微观机制的演化关系。建立了一种合适的状态变量方法来耦合蠕变应变-时间轨迹上的初始微观结构状态及其演化过程的相互作用。重点将放在实验推导非弹性应变方程，该方程可用于预测模拟活动中塑性应变的演变。

The overall aim of the project is to develop a microstructure-sensitive constitutive description of creep of gamma prime strengthened superalloys under extreme temperature conditions. The temperature range of interest will be between 1300oC and 1150oC with specific consideration to re-crystallisation during subsequent heat treatment in turbine blades. The work will involve identification of dominant deformation mechanisms and understanding of the microstructure in the conditions of interest, specifically through the use of miniature testing with small gauge volumes of the order of the length scale of micro-segregation. From this information, it is hoped to derive evolution relations for the micro-mechanisms. An appropriate state variable approach will be developed to couple the interaction of the initial microstructure state and its evolution on the creep strain-time trajectories. An emphasis will be placed on experimentally deriving an equation for the inelastic strain that can be used to predict the evolution of plastic strain in modelling activities.