首页|Effect of multilevel lamellar microstructures on notch high cycle fatigue damage micromechanism of TC21 alloy
Effect of multilevel lamellar microstructures on notch high cycle fatigue damage micromechanism of TC21 alloy
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NETL
NSTL
Elsevier
Effect of multilevel lamellar microstructures (MLMs) on notch high cycle fatigue (NHCF) property and micro-crack initiation behavior of TC21 alloy were systematically investigated. The MLMs was created via a triple heat treatment, including parallel-aligned a laths (α_(lath)) within the a colony (α_c) and aged a fine lamellae (α_(fine)) in the p transformation matrix (β_(trans))- Results indicate that microstructural refinement and an increase in heterogeneous regions adversely affect NHCF properties. Most microcracks initiate within slip and shear deformation bands located in heterogeneous areas, which act as fatal sites for fatigue damage. The activation of early {0002}_α basal slip and subsequent formation of {l102}_α pyramidal slip are main driver that contribute to the initiation of microvoids and microcracks within the a phase. Localized uneven deformation is a prerequisite for the activation of basal slip. Moreover, under higher cyclic stress and lower α_2 nanoparticles content, both basal slip and pyramidal slip coexist within the α_(lath) resulting in the formation of cross persistent slip bands (PSBs) and localized hardening. This process further facilitates the initiation of microvoids and microcracks within the α_(lath)- Crucially, the initial slip of dislocations and their interactions with interfaces also contribute to microvoids formation.
TC21 alloyMultilevel lamellar microstructureNotch high cycle fatigueFatigue microcrack initiation mechanism
Xiang Li、Chaowen Huang、Jiang Yang、Dan Liu、Tianxin Li、Changsheng Tan、Weiju Jia、Mingpan Wan
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National and Local Joint Engineering Laboratory for High-Performance Metal Structure Materials and Advanced Manufacturing Technology, Guizhou University, Guiyang 550025, China
School of Materials and Energy Engineering, Guizhou Institute of Technology, Guiyang 550003, China
Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China
NETL
NSTL
Elsevier
