Altered ageing behaviour of a nanostructured Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy processed by high pressure torsion
Source abstract
Abstract
Abstract In this study, the ageing behaviour of a nanostructured Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt.%) alloy produced by solution treatment followed by high pressure torsion (HPT) was systematically investigated using hardness testing, high resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), elemental mapping, X-ray diffraction (XRD) and XRD line broadening analysis. The HPT-deformed alloy exhibits an ageing response that produces a higher peak-aged hardness at lower temperature and shorter ageing time as compared to the same alloy aged after conventional thermomechanical processing. The HAADF-STEM and elemental mapping reveal extensive segregation of solute atoms along grain boundaries during ageing. A model is developed which shows that the main structures causing hardening for peak-aged samples are the grain boundaries and the segregation of solute atoms formed along grain boundaries. The metastable β′ phase precipitates, which form on ageing of conventionally processed Mg-Gd-Y-Zn-Zr alloy samples, do not form in the present aged samples, and instead equilibrium β-Mg5(RE,Zn) phase forms on over-ageing. This altered precipitation behaviour is attributed to the high defect density (e.g. grain boundaries, dislocations and vacancies) introduced by HPT, leading to enhanced diffusion of solutes. The present processing produces an alloy that has a hardness of ∼145 HV. A model of strengthening indicates that whilst grain boundary strengthening provides the largest contribution to strengthening, it is the additional solid solution hardening, cluster hardening, and dislocation hardening that provide the main factors that caused the hardness to surpass that of other bulk processed Mg alloys studied to date.
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Research context
OpenAlex topics: Magnesium Alloys: Properties and Applications · Aluminum Alloys Composites Properties · Metal and Thin Film Mechanics
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (73)
Show source-provided references
1. Magnesium: properties-applications potential10.1016/S0921-5093(00)01351-4 ↗
2. Rapidly solidified powder metallurgy Mg97Zn1Y2 alloys with excellent tensile yield strength above 600 MPa10.2320/matertrans.42.1172 ↗
3. Effect of long-period stacking ordered phase on mechanical properties of Mg97Zn1Y2 extruded alloy10.1016/j.actamat.2010.07.050 ↗
4. Microstructure and mechanical properties of Mg-Gd-Y-Zn-Zr alloy sheets processed by extrusion, hot rolling and ageing10.1016/j.msea.2012.09.032 ↗
5. Current research progress in grain refinement of cast magnesium alloys: a review article10.1016/j.jallcom.2014.09.061 ↗
6. Study of Mg-Gd-Zn-Zr alloys with long period stacking ordered structures10.1016/j.msea.2013.07.049 ↗
7. Superplasticity and microstructural stability in a Mg alloy processed by hot rolling and friction stir processing10.1016/j.scriptamat.2012.11.009 ↗
8. Formation of profuse long period stacking ordered microcells in Mg-Gd-Zn-Zr alloy during multipass ECAP process10.1016/j.jallcom.2014.02.175 ↗
9. Bulk nanostructured materials from severe plastic deformation10.1016/S0079-6425(99)00007-9 ↗
10. Using high-pressure torsion for metal processing: fundamentals and application10.1016/j.pmatsci.2008.03.002 ↗
11. Atomic-scale analysis of the segregation and precipitation mechanisms in a severely deformed Al-Mg alloy10.1016/j.actamat.2014.03.033 ↗
12. Investigation of precipitation effects in Mg-Tb and Mg-Tb-Nd alloys10.12693/APhysPolA.125.744 ↗
13. Structure and mechanical properties of the Mg-Y-Gd-Zr alloy after high pressure torsion10.1016/j.msea.2016.05.003 ↗
14. Effect of cooling rate on the microstructure evolution and mechanical properties of homogenized Mg-Gd-Y-Zn-Zr alloy10.1016/j.msea.2012.08.112 ↗
15. Microstructure and mechanical properties of a nanostructured Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr supersaturated solid solution prepared by high pressure torsion10.1016/j.matdes.2017.09.048 ↗
16. Predicting grain refinement by cold severe plastic deformation in alloys using volume averaged dislocation generation10.1016/j.actamat.2009.08.006 ↗
17. The intercept method-1. Evaluation of grain shape10.1016/S1359-6454(96)00197-8 ↗
18. Microstructural evolution, strengthening and thermal stability of an ultrafine-grained Al-Cu-Mg alloy10.1016/j.actamat.2016.02.050 ↗
19. Method for the simultaneous determination of anisotropic residual stresses and texture by X-ray diffraction10.1063/1.358006 ↗
20. X-ray diffraction characterization of heavily deformed metallic specimens10.1016/S1359-6454(97)00222-X ↗
21. Strengthening of an Al-Cu-Mg alloy processed by high-pressure torsion due to clusters, defects and defect-cluster complexes10.1016/j.msea.2014.12.107 ↗
22. Dislocation densities in some annealed and cold-worked metals from measurements on the X-Ray Debye-Scherrer spectrum10.1080/14786435608238074 ↗
23. Effect of ageing treatment on the microstructure, texture and mechanical properties of extruded Mg-8.2Gd-3.8Y-1Zn-0.4Zr (wt%) alloy10.1016/j.msea.2012.11.125 ↗
24. Ultra high-strength Mg-Gd-Y-Zn-Zr alloy sheets processed by large-strain hot rolling and ageing10.1016/j.msea.2012.03.087 ↗
25. Effect of ageing treatment on the precipitation behaviour of Mg-Gd-Y-Zn-Zr alloy10.1016/j.jallcom.2012.09.101 ↗
26. Precipitation in a Mg-10Gd-3Y-0.4Zr (wt.%) alloy during isothermal ageing at 250°C10.1016/j.jallcom.2005.11.046 ↗
27. Precipitation and hardening in magnesium alloys10.1007/s11661-012-1217-2 ↗
28. Microstructure of two-phase Al-1.7 at% Cu alloy deformed by equal-channel angular pressing10.1016/S1359-6454(00)00308-6 ↗
29. Al-Mg-Cu based alloys and pure Al processed by high pressure torsion: the influence of alloying additions on strengthening10.1016/j.msea.2010.02.016 ↗
30. Nickel segregation on dislocation loops in implanted silicon10.1016/j.scriptamat.2010.10.036 ↗
31. Specimen preparation methods for elemental characterisation of grain boundaries and isolated dislocations in multicrystalline silicon using atom probe tomography10.1016/j.matchar.2017.07.038 ↗
32. On the temperature dependent strengthening of nickel by transition metal solutes10.1016/j.actamat.2017.05.038 ↗
33. Solute effects on edge dislocation pinning in complex alpha-Fe alloys10.1016/j.jnucmat.2017.07.049 ↗
34. Grain boundary segregation induced strengthening of an ultrafine-grained austenitic stainless steel10.1016/j.matlet.2014.07.188 ↗
35. Direct observation of dislocation dissociation and Suzuki segregation in a Mg-Zn-Y alloy by aberration-corrected scanning transmission electron microscopy10.1016/j.actamat.2012.09.067 ↗
36. McLean · 1957
37. Effect of rare-earth additions on the texture of wrought magnesium alloys: the role of grain boundary segregation10.1007/s11661-013-1950-1 ↗
38. Grain boundary segregation of rare-earth elements in magnesium alloys10.1007/s11661-015-3199-3 ↗
39. Short-circuit diffusion in an ultrafine-grained copper-zirconium alloy produced by equal channel angular pressing10.1016/j.actamat.2007.07.026 ↗
40. Persistence of ultrafast atomic diffusion paths in recrystallizing ultrafine grained Ni10.1016/j.scriptamat.2015.01.027 ↗
41. General relationship between strength and hardness10.1016/j.msea.2011.08.061 ↗
42. Hardening of pure metals by high-pressure torsion: a physically based model employing volume-averaged defect evolutions10.1016/j.actamat.2012.09.048 ↗
43. Multi-component solid solution hardening10.1007/BF00540987 ↗
44. Strengthening mechanisms in solid solution aluminum alloys10.1007/s11661-006-0142-7 ↗
45. Effects of rare-earth elements Gd and Y on the solid solution strengthening of Mg alloys10.1016/j.jallcom.2009.02.131 ↗
46. The thermodynamics of and strengthening due to co-clusters: general theory and application to the case of Al-Cu-Mg alloys10.1016/j.actamat.2009.01.021 ↗
47. A model for the thermodynamics of and strengthening due to co-clusters in Al-Mg-Si-based alloys10.1016/j.actamat.2012.04.032 ↗
48. Room temperature precipitation in quenched Al-Cu-Mg alloys: a model for the reaction kinetics and yield strength development10.1080/14786430412331333374 ↗
49. Classification of bulk metallic glasses by atomic size difference, heat of mixing and period of constituent elements and its application to characterization of the main alloying element10.2320/matertrans.46.2817 ↗
50. Underwood · 1970
51. Rokhlin · 2003
52. Pressure and temperature derivatives of the isotropic polycrystalline shear modulus for 65 elements10.1016/S0022-3697(74)80278-7 ↗
53. The effect of size and distribution of rod-shaped precipitates on the strength and ductility of a Mg-Zn alloy10.1016/j.msea.2012.01.087 ↗
54. Dieter · 1986 · 212
55. Consideration of Orowan strengthening effect in particulate-reinforced metal matrix nanocomposites: a model for predicting their yield strength10.1016/j.scriptamat.2005.12.017 ↗
56. Ultrafine grain formation in Mg-Zn alloy by in situ precipitation during high-pressure torsion10.1016/j.scriptamat.2014.01.036 ↗
57. Grain size and microhardness evolution during annealing of a magnesium alloy processed by high-pressure torsion10.1016/j.jmrt.2014.10.008 ↗
58. Effect of temperature on the processing of a magnesium alloy by high-pressure torsion10.1007/s10853-012-6578-9 ↗
59. Evolution of strength and homogeneity in a magnesium AZ31 alloy processed by high-pressure torsion at different temperatures10.1002/adem.201200016 ↗
60. Mechanical properties and microstructure evolution in ultrafinegrained AZ31 alloy processed by severe plastic deformation10.1007/s10853-013-7151-x ↗
61. Interpretation of hardness evolution in metals processed by high-pressure torsion10.1007/s10853-014-8262-8 ↗
62. Developing grain refinement and superplasticity in a magnesium alloy processed by high-pressure torsion10.1016/j.msea.2007.12.046 ↗
63. Enhancement of the mechanical properties of an Mg-Zn-Ca alloy using high-pressure torsion10.1002/adem.201500176 ↗
64. Evolution in hardness and texture of a ZK60A magnesium alloy processed by high-pressure torsion10.1016/j.msea.2015.02.011 ↗
65. Evolution in hardness and microstructure of ZK60A magnesium alloy processed by high-pressure torsion10.1016/j.jmrt.2014.10.015 ↗
66. Properties of a ZK60 magnesium alloy processed by high-pressure torsion10.1016/j.jallcom.2014.06.056 ↗
67. Simultaneously enhanced strength and ductility of Mg-Zn-Zr-Ca alloy with fully recrystallized ultrafine grained structures10.1016/j.scriptamat.2016.12.024 ↗
68. Superplastic behavior of magnesium-based Mg-10 wt% Gd alloy after severe plastic deformation by torsion10.1134/S0031918X0606010X ↗
69. Nucleation of recrystallized magnesium grains over quasicrystalline phase during severe plastic deformation of a Mg-Zn-Y alloy at room temperature10.1016/j.scriptamat.2017.02.039 ↗
70. Texture, deformation twinning and hardening in a newly developed Mg-Dy-Al-Zn-Zr alloy processed with high pressure torsion10.1016/j.matdes.2015.11.062 ↗
71. Localized deformation via multiple twinning in a Mg-Gd-Y-Zr alloy processed by high-pressure torsion10.1016/j.msea.2016.09.005 ↗
72. Evolution of microstructure and mechanical properties of an as-cast Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy processed by high pressure torsion10.1016/j.msea.2017.05.115 ↗
73. Dislocation versus grain boundary strengthening in SPD processed metals: non-causal relation between grain size and strength of deformed polycrystals10.1016/j.msea.2017.08.069 ↗