Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment

Al–Mg-Sc-Zr alloys with flat surface, low porosity and excellent mechanical properties were prepared by Laser Metal Deposition (LMD) and annealed (A) using secondary recycled Al–Mg-Sc-Zr powders in an open environment. The optimal LMD parameters are laser power 1800 W, scanning speed 5 mm/s and scan...

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Main Authors: Xiao Liu, Li Xie, Gang Xiao, Biwu Zhu, Chao Lu, Wenhui Liu
Format: Article
Language:English
Published: Elsevier 2024-11-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S223878542402684X
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author Xiao Liu
Li Xie
Gang Xiao
Biwu Zhu
Chao Lu
Wenhui Liu
author_facet Xiao Liu
Li Xie
Gang Xiao
Biwu Zhu
Chao Lu
Wenhui Liu
author_sort Xiao Liu
collection DOAJ
description Al–Mg-Sc-Zr alloys with flat surface, low porosity and excellent mechanical properties were prepared by Laser Metal Deposition (LMD) and annealed (A) using secondary recycled Al–Mg-Sc-Zr powders in an open environment. The optimal LMD parameters are laser power 1800 W, scanning speed 5 mm/s and scanning spacing 3 mm The Al–Mg-Sc-Zr alloy deposited by multi-layer multi-track under optimal parameters and subsequent annealing treatment displays a flat surface, porosity of 2.08%, hardness of 134 HV, ultimate tensile strengthen (UTS) of 348 MPa, yield strength (YS) of 235 MPa and uniform elongation (εu) of 16.71%. The porosity mainly concentrates in the molten pool overlap due to the influence of Marangoni convection. Solute redistribution and compositional subcooling lead to periodic segregation of Sc elements, finally contributing to the appearance of bright and dark spiral stacking features centered in the molten pool. Due to the small G/R value of the molten pool, coarse and fine equiaxed grains are alternately developed during single-track deposition. The in-situ heat treatment induced by the subsequent multi-layer multi-track deposition transformed the alternately distributed coarse and fine equiaxed grain structure into a homogeneous grain structure. This results from the combination influence of the difference in the proportion of large-angle grain boundaries occupied by the coarse/fine grains and the pinning of the Al3(Sc,Zr) grains. The strength of the present alloy is mainly provided by solid solution strengthening, fine grain strengthening and second phase strengthening. The stress concentration is reduced for fine grain size and the intergranular strain transfer is favored because of small internal orientation difference. Meanwhile, the interlayer retention and annealing treatment timely release the thermal stresses during the LMD process, which results in the Al–Mg-Sc-Zr alloys keep good plasticity.
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publishDate 2024-11-01
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spelling doaj-art-178de0c7fc5c4b00b5302e49c50e9bd82024-12-26T08:55:45ZengElsevierJournal of Materials Research and Technology2238-78542024-11-013380408048Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environmentXiao Liu0Li Xie1Gang Xiao2Biwu Zhu3Chao Lu4Wenhui Liu5College of Marine Equipment and Mechanical Engineering, Jimei University, Xiamen, 361021, China; School of Mechanical Engineering, Hunan University of Science and Technology, Xiangtan, 411201, ChinaSchool of Mechanical Engineering, Hunan University of Science and Technology, Xiangtan, 411201, ChinaJiangxi Copper Technology Research Institute Co., Ltd., Nanchang, 330096, China; Corresponding author.College of Marine Equipment and Mechanical Engineering, Jimei University, Xiamen, 361021, China; Corresponding author.School of Materials Science and Engineering, Guangdong Ocean University, Yangjiang, 529500, ChinaCollege of Marine Equipment and Mechanical Engineering, Jimei University, Xiamen, 361021, ChinaAl–Mg-Sc-Zr alloys with flat surface, low porosity and excellent mechanical properties were prepared by Laser Metal Deposition (LMD) and annealed (A) using secondary recycled Al–Mg-Sc-Zr powders in an open environment. The optimal LMD parameters are laser power 1800 W, scanning speed 5 mm/s and scanning spacing 3 mm The Al–Mg-Sc-Zr alloy deposited by multi-layer multi-track under optimal parameters and subsequent annealing treatment displays a flat surface, porosity of 2.08%, hardness of 134 HV, ultimate tensile strengthen (UTS) of 348 MPa, yield strength (YS) of 235 MPa and uniform elongation (εu) of 16.71%. The porosity mainly concentrates in the molten pool overlap due to the influence of Marangoni convection. Solute redistribution and compositional subcooling lead to periodic segregation of Sc elements, finally contributing to the appearance of bright and dark spiral stacking features centered in the molten pool. Due to the small G/R value of the molten pool, coarse and fine equiaxed grains are alternately developed during single-track deposition. The in-situ heat treatment induced by the subsequent multi-layer multi-track deposition transformed the alternately distributed coarse and fine equiaxed grain structure into a homogeneous grain structure. This results from the combination influence of the difference in the proportion of large-angle grain boundaries occupied by the coarse/fine grains and the pinning of the Al3(Sc,Zr) grains. The strength of the present alloy is mainly provided by solid solution strengthening, fine grain strengthening and second phase strengthening. The stress concentration is reduced for fine grain size and the intergranular strain transfer is favored because of small internal orientation difference. Meanwhile, the interlayer retention and annealing treatment timely release the thermal stresses during the LMD process, which results in the Al–Mg-Sc-Zr alloys keep good plasticity.http://www.sciencedirect.com/science/article/pii/S223878542402684XLaser metal depositionAl–Mg-Sc-Zr alloysProcess optimizationMicrostructureMechanical property
spellingShingle Xiao Liu
Li Xie
Gang Xiao
Biwu Zhu
Chao Lu
Wenhui Liu
Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment
Journal of Materials Research and Technology
Laser metal deposition
Al–Mg-Sc-Zr alloys
Process optimization
Microstructure
Mechanical property
title Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment
title_full Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment
title_fullStr Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment
title_full_unstemmed Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment
title_short Microstructural evolution and mechanical properties of Laser Metal Deposition Al–Mg-Sc-Zr alloy using recycled powders in an open environment
title_sort microstructural evolution and mechanical properties of laser metal deposition al mg sc zr alloy using recycled powders in an open environment
topic Laser metal deposition
Al–Mg-Sc-Zr alloys
Process optimization
Microstructure
Mechanical property
url http://www.sciencedirect.com/science/article/pii/S223878542402684X
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