Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, Krakow, Poland.
J Microsc. 2010 Mar;237(3):364-9. doi: 10.1111/j.1365-2818.2009.03261.x.
TEM studies of creep tested CMSX-4 nickel-base single crystal superalloy were performed to analyse a microstructure evolution during creep at temperature 750 degrees C, and uniaxial tensile stress of 675 MPa. Microstructural analyses were focused mainly on examination of dislocation configurations during primary and secondary creep stages of high temperature deformation. At such low temperature and high stress creep deformation proceed by cutting of gamma' particles by dislocations. It was found that primary creep is initiated by movement of dislocations with Burgers vector a/2 <110> in the gamma phase. The second type of dislocations active at primary creep stage are extended dislocation ribbons with overall a<112> Burgers vector, separated by superlattice stacking faults, cutting both the gamma and gamma' phases. The movement of the dislocation ribbons is inhibited at secondary creep stage by dislocation networks formed at gamma-gamma' interfaces.
采用透射电子显微镜研究了 CMSX-4 镍基单晶高温合金在 750℃和 675MPa 单向拉伸条件下的蠕变行为，分析了在蠕变过程中的微观组织演变。主要研究了高温变形的初始蠕变和二次蠕变阶段位错组态。在如此低的温度和高应力下，蠕变变形是通过位错切割 γ' 颗粒来进行的。研究发现，初始蠕变是由位错以<110>方向的 Burgers 矢量 a/2 运动引起的，在 γ 相中。在初始蠕变阶段，第二种活性位错是具有整体 a<112> Burgers 矢量的扩展位错带，由超晶格堆垛层错分隔，切割 γ 和 γ'相。在二次蠕变阶段，位错网络的形成抑制了位错带的运动，这些位错网络形成于 γ-γ'界面处。
