摘要
通过蠕变性能测试及组织形貌观察,研究了热连轧直接时效处理的GH4169镍基合金的蠕变行为和断裂机制。结果表明:热连轧GH4169镍基合金的组织结构由γ′,γ″相和γ基体相组成,具有较小的晶粒尺寸,晶内存在高密度位错和孪晶。经直接时效后,合金中弥散分布的细小γ″相数量增加,及高密度位错引起的形变强化效果,是使合金在650℃/725MP条件下具有较长的蠕变寿命的主要原因;蠕变期间,合金的变形特征是孪晶变形和位错的双取向滑移;随着蠕变进行,位错的数量逐渐增加,并在晶界处引起应力集中,致使裂纹在晶界处萌生及扩展是合金的蠕变断裂机制。
By means of the creep curves measurement and microstructure observation,the creep behavior and fracture mechanism of HCR ＋ DA GH4169 nickel-base superalloy are investigated.Results show that microstructure of HCR GH4169 alloy consists of the γ′,γ″ phase and γ matrix,and possessing in the fine grains in which exists significant amount of dislocations and twinning.After direct aged treated.the quantities of the dispersed fine γ″ phase increases and the alloy retains the effect of the deformed strenghtening during hot continuous rolling,which is thought to be the main cause of the alloy possessing a longer creep lifetime under the applied stress of 725 MPa at 650℃.During creep,the deformation features of the alloy are twining and double orientation slipping of the dislocations.As the creep goes on,significant amount of dislocations is plied up the regions near the boundaries to bring out the stress concentration,which results in the initiation and propagation of the micro-cracks along the boundaries up to rupture.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2011年第5期71-76,75-76,共6页
Journal of Aeronautical Materials
基金
国家自然科学基金资助的重点项目:50634030
