Enhancing fatigue performance of AZ31 magnesium alloy components fabricated by cold metal transfer-based wire arc directed energy deposition through LPB

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外文摘要：Cold metal transfer-based wire arc directed energy deposition(CMT-WA-DED)presents a promising avenue for the rapid fabrication of com-ponents crucial to automotive,shipbuilding,and aerospace industries.However,the susceptibility to fatigue of CMT-WA-DED-produced AZ31 Mg alloy components has impeded their widespread adoption for critical load-bearing applications.In this study,a comprehensive investigation into the fatigue behaviour of WA-DED-fabricated AZ31 Mg alloy has been carried out and compared to commercially available wrought AZ31 alloy.Our findings indicate that the as-deposited parts exhibit a lower fatigue life than wrought Mg alloy,primarily due to poor surface finish,tensile residual stress,porosity,and coarse grain microstructure inherent in the WA-DED process.Low Plasticity Burnishing(LPB)treatment is applied to mitigate these issues,which induce significant plastic deformation on the surface.This treatment resulted in a remarkable improve-ment of fatigue life by 42％,accompanied by a reduction in surface roughness,grain refinement and enhancement of compressive residual stress levels.Furthermore,during cyclic deformation,WA-DED specimens exhibited higher plasticity and dislocation density compared to both wrought and WA-DED+LPB specimens.A higher fraction of low angle grain boundaries(LAGBs)in WA-DED specimens contributed to mul-tiple crack initiation sites and convoluted crack paths,ultimately leading to premature failure.In contrast,wrought and WA-DED+LPB speci-mens displayed a higher percentage of high angle grain boundaries(HAGBs),which hindered dislocation movement and resulted in fewer crack initiation sites and less complex crack paths,thereby extending fatigue life.These findings underscore the effectiveness of LPB as a post-pro-cessing technique to enhance the fatigue performance of WA-DED-fabricated AZ31 Mg alloy components.Our study highlights the importance of LPB surface treatment on AZ31 Mg components produced by CMT-WA-DED to remove surface defects,enabling their widespread use in load-bearing applications.

外文关键词：

Wire arc additive manufacturingAZ31 Mg alloyLow plasticity burnishingLow cycle fatigue testStrain amplitude

作者：

Shambhu Kumar Manjhi、Srikanth Bontha、A.S.S.Balan

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作者单位：

Department of Mechanical Engineering,National Institute of Technology Kamataka,Surathkal,Srinivasanagar,Mangalore,Karnataka 575 025,India

基金：

Department of Science and Technology Government of IndiaFronius India Solutions & Skill Centre,Bengaluru and CRF NITK Surathkal

项目编号：

SP/YO2019/1287G

出版年：

2024

DOI：

10.1016/j.jma.2024.04.016

镁合金学报(英文)

ISSN：2213-9567

年,卷(期)：2024.12(4)