Abstract The local compositional changes associated with stacking fault and microtwin formation during creep at intermediate temperatures in a commercial Ni-base disk superalloy are explored. In order to investigate microtwin formation, an [001] single crystal of ME3 was tested in compression at 760 °C under a stress of 414 MPa – a stress-temperature regime found to promote microtwinning. Atomic resolution scanning transmission electron microscopy combined with state-of-the-art energy dispersive X-ray (EDX) spectroscopy analysis reveals the presence of Co and Cr rich Cottrell atmospheres around leading dislocations responsible for the creation of SISFs, SESFs, and microtwins. This analysis also highlights the role that tertiary γ particles inside γ′ precipitates have on γ′ shearing deformation mechanisms. Through the use of CALPHAD calculations, combined with new experimental observations, new insights into the rate-controlling processes during creep deformation are discussed.

中文翻译：

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镍基高温合金中温蠕变过程中的扩散过程

摘要 探讨了商业镍基圆盘高温合金在中等温度蠕变过程中与堆垛层错和微孪晶形成相关的局部成分变化。为了研究微孪晶的形成，在 760°C 和 414 MPa 的压力下对 ME3 的 [001] 单晶进行了压缩测试 - 发现促进微孪晶的应力 - 温度范围。原子分辨率扫描透射电子显微镜结合最先进的能量色散 X 射线 (EDX) 光谱分析揭示了在导致 SISF、SESF 和微孪晶形成的主要位错周围存在富含 Co 和 Cr 的 Cottrell 气氛。该分析还强调了 γ' 沉淀物中的三次 γ 粒子对 γ' 剪切变形机制的作用。通过使用 CALPHAD 计算，