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Hydrogenation effect on microstructure and mechanical properties of Mg-Gd-Y-Zn-Zr alloys
journal contribution
posted on 2018-03-14, 00:00 authored by Rimma LapovokRimma Lapovok, E Zolotoyabko, A Berner, V Skripnyuk, E Lakin, N Larianovsky, C Xu, E RabkinThis work explores the ways of manipulating the microstructure and mechanical properties of Mg-Gd-Y-Zn-Zr alloys of various compositions using hydrogen treatment. Changes to phase composition, microstructure, and mechanical properties of the alloys upon hydrogenation were studied. Prior to hydrogenation, the alloys were extruded at different temperatures with or without subsequent aging. Hydrogen treatment was performed on bulk rods after thermo-mechanical processing. X-ray diffraction and scanning electron microscopy studies showed that a single rare-earth (RE) hydride phase, Gd0.5Y0.5H2, was formed in all samples. As a result, the 14H long period stacking ordered (LPSO) structure, detected before hydrogenation, is completely destroyed due to the clustering of RE atoms into large hydride crystals and annihilation of the specific spatial order within the superlattice. Prolonged hydrogen treatment at high temperature (≈ 0.74·Tm) causes recrystallization and grain growth in the magnesium matrix, defect annealing and reduction of preferred orientation, which together with the complete destruction of the LPSO phase lead to the substantial decrease of alloys’ strength and concomitant increase of their ductility to the record-high value of above 20%.
History
Journal
Materials science and engineering AVolume
719Pagination
171 - 177Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0921-5093Language
engPublication classification
C1 Refereed article in a scholarly journalCopyright notice
2018, Elsevier B.V.Usage metrics
Keywords
Mg-RE alloysLPSO phaseHydrogenationRE-hydridesMechanical propertiesMicrostructureScience & TechnologyTechnologyNanoscience & NanotechnologyMaterials Science, MultidisciplinaryMetallurgy & Metallurgical EngineeringScience & Technology - Other TopicsMaterials ScienceSTACKING ORDERED STRUCTUREMAGNESIUM ALLOYPHASEEXTRUSIONSTRENGTHBEHAVIORSTORAGEDIFFUSIONTEXTUREMechanical Engineering
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