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| Influence of MgAl precipitates on the evolutionary behaviour of subsurface organization and wear properties of WAAM magnesium alloys |
| ZOU Ting，ZENG Jia，YANG Junjie，LI Jie，WANG Qiwei，LI Wei |
| （Institute of advanced wear & corrosion resistant and functional materials, Jinan University, Guangzhou 510632，China） |
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Abstract Three magnesium alloys(WAAM AZ31， AZ61， and AZ91) with different MgAl phase content were manufactured by the wire arc additive manufacturing(WAAM). The abrasive wear behavior of three WAAM mag‐ nesium alloys was compared, and the abrasive surface and subsurface abrasive morphology were examined by OM, SEM, and EBSD. It is shown that based on the ploughing of the wear scar surface, the loss of material during the wear process mainly originates from microcutting. At the same time, a deformation layer rich in twins and small angular grain boundaries is formed above the subsurface matrix layer of the wear scar. The wear resistance of magnesium alloys is influenced by the hardness of the deformation layer and the content of precipitates. Thus, although the matrix hardness and MgAl precipitates content of AZ61 increase by 10.8 %（1. 02→1. 13 GPa）and 77.8 %（1. 8→3. 2 %）respectively compared to AZ31， the wear resistance is only increased by 4. 2 %（1. 41→ 1. 35 mm3）due to the reduction in the hardness of the deformation layer（1. 61→1. 50 GPa）. Correspondingly although the matrix hardness and MgAl precipitates content of AZ91 are only 13. 7 %（1. 13→1. 28 GPa）and 28.1% （3. 2%→4. 1%）higher than those of AZ61， respectively, the wear resistance is significantly increased by 26.7% （1. 35→0.99 mm3）due to a slight increase in deformation layer hardness（1. 50→1. 51 GPa）. The hardness of the deformation layer is influenced by the combined effect of diffuse reinforcement of the precipitates and the inhibi‐ tion of twin crystal formation.
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Received: 02 November 2022
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Corresponding Authors:
李 杰（1985—），男，博士，讲师，主要研究方向为金属材料磨损机制、新材料开发等。
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2023, Vol. 33 
