We build a crystal plasticity finite element framework to investigate slip localisation and fatigue-creep behaviour at the cooling holes of single crystal Nickel (Ni) based components under cyclic thermomechanical loading. The total slip rate is decomposed into a thermally activated dislocation glide rate which dominates at moderate/low temperatures ($T$) and/or high stresses, and a climb rate which dominates at high temperatures and increases as inelastic strain accumulates. This formulation captures the monotonic and long-term creep response of Ni alloys in the wide range 20 <$T$ < 1100 °C and indicates that room temperature plasticity during unloading increases the high temperature creep rate during loading (creep dwell), eventually increasing the total slip accumulation per cycle; the effect depends on the way the inelastic strain accumulates upon successive slip reversals. Elastic material anisotropy is shown to modify drastically the stress concentration around holes such that slip tends to localise at locations where the max principal stress, tangent to the hole surface, aligns with stiff crystallographic directions. This highlights the importance of plastic and creep anisotropy and creates new avenues for optimising hole shape to minimise slip activity. Our study brings to light key material-component relationships that concern the wider material science, high temperature and fatigue communities.

我们建立了一个晶体塑性有限元框架来研究单晶镍 (Ni) 基部件在循环热机械载荷下的冷却孔处的滑移定位和疲劳蠕变行为。总滑移率分解为热激活位错滑移率，它在中/低温下占主导地位（$吨$) 和/或高应力，以及在高温下占主导地位并随着非弹性应变累积而增加的爬升率。该公式捕捉了镍合金在宽范围内的单调和长期蠕变响应 20 <$吨$< 1100 °C，表明卸载期间的室温塑性增加了加载期间的高温蠕变速率（蠕变保压），最终增加了每个循环的总滑移积累；这种影响取决于非弹性应变在连续滑移反转时的累积方式。弹性材料各向异性被证明可以显着改变孔周围的应力集中，使得滑移倾向于局部化在最大主应力（与孔表面相切）与刚性晶体方向对齐的位置。这突出了塑性和蠕变各向异性的重要性，并为优化孔形状以最大限度地减少滑动活动创造了新途径。我们的研究揭示了涉及更广泛的材料科学、高温和疲劳社区的关键材料-成分关系。