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对伽马强化高温合金在极端温度条件下的蠕变的微观结构敏感的本构描述。感兴趣的温度范围将在1300oC到1150oC之间，并特别考虑在涡轮叶片随后的热处理过程中重新结晶。这项工作将包括确定主要的变形机制和了解感兴趣的条件下的微观结构，特别是通过使用微观偏析长度尺度量级的小尺寸体积的微型测试。从这些信息中，人们希望推导出微观机制的演化关系。发展了一种适当的状态变量方法来耦合初始微结构状态及其在蠕变应变-时间轨迹上的演化。重点将放在从实验上推导出可用于预测模拟活动中塑性应变演化的非弹性应变方程。

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.