Micro-strain and cyclic slip accumulation in a polycrystalline nickel-based superalloy
Micro-strain and cyclic slip accumulation in a polycrystalline nickel-based superalloy
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多晶镍基高温合金中的微应变和循环滑移累积
DOI：
10.1016/j.actamat.2024.119657
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发表时间：
2024-01
期刊：
影响因子：
9.4
通讯作者：
R.L. Black;D. Anjaria;J. Genée;V. Valle;J. Stinville
中科院分区：
文献类型：
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作者：
R.L. Black;D. Anjaria;J. Genée;V. Valle;J. Stinville
这项工作对镍基高温合金在环境温度疲劳期间的变形和疲劳损伤机制进行了全面的表征和分析，并指出了导致裂纹形核发生的基本变形机制。使用高分辨率数字图像相关和高分辨率电子背散射衍射在纳米尺度上研究应变和滑移不可逆性，突出了导致裂纹成核的不同变形机制。在早期疲劳循环期间，在相对较低的施加应力下观察到，形成强烈的滑移事件，从而引起晶界剪切。这会导致相邻晶粒产生强烈的微观应变，产生局部塑性和应力。这种应力有利于后续循环过程中的疲劳挤压-侵入机制，从而导致优选的裂纹形核。最后，强调了促进这种变形和损坏机制序列的微观结构内的配置。
This work provides a comprehensive characterization and analysis of deformation and fatigue damage mechanisms in a nickel-based superalloy during ambient temperature fatigue and points to a fundamental deformation mechanism that results in the onset of crack nucleation. Strain and slip irreversibility are investigated at the nanometer scale using high-resolution digital image correlation and high-resolution electron backscatter diffraction, highlighting distinct deformation mechanisms contributing to crack nucleation. It is observed during early fatigue cycling at relatively low applied stress, the formation of intense slip events that induce grain boundary shearing. This results in intense micro-scale strain in the neighboring grains, producing localized plasticity and stresses. Such stresses facilitate fatigue extrusion–intrusion mechanisms during subsequent cycling, resulting in preferred crack nucleation. Finally, the configurations within the microstructure that promote such deformation and damage mechanisms sequence are highlighted.