Influence of high-pressure torsion on microstructure, hardness and shear strength of AM60 magnesium alloy

0540444 - ÚJF 2022 RIV CH eng J - Journal Article
Khaleghi, A. A. - Akbaripanah, F. - Sabbaghian, M. - Mathis, Kristián - Minárik, P. - Veselý, J. - El-Tahawy, M. - Gubicza, J.
Influence of high-pressure torsion on microstructure, hardness and shear strength of AM60 magnesium alloy.
Materials Science and Engineering A Structural Materials Properties Microstructure and Processing. Roč. 799, JAN (2021), č. článku 140158. ISSN 0921-5093. E-ISSN 1873-4936
R&D Projects: GA MŠMT EF16_013/0001794
Institutional support: RVO:61389005
Keywords : AM60 * hardness * high-pressure torsion * magnesium alloys * shear punch test * texture
OECD category: Materials engineering
Impact factor: 6.044, year: 2021
Method of publishing: Limited access
https://doi.org/10.1016/j.msea.2020.140158

The evolution of the microstructure, crystallographic texture and hardness of an AM60 magnesium alloy was studied in the center and the edge parts of disks processed by high-pressure torsion (HPT) technique at room temperature. In addition, the mechanical properties were also tested by shear punch test (SPT). The number of HPT turns varied between ½ and 10. It was found that the grain size of the initial extruded material (∼16 μm) decreased to ∼2 and ∼0.8 μm at the disk center and edge, respectively, even after ½ turn of HPT. Ten turns of HPT resulted in further grain refinement to ∼1 and ∼0.23 μm at the disk center and edge, respectively. The dislocation density saturated even after ½ turn with the value of ∼11 × 1014 m−2. The maximum value of the hardness was ∼1300 MPa that was measured at the edge of the disk deformed for ½ turn. Despite the practically unchanged grain size and dislocation density, the hardness decreased between 3 and 10 turns which can be explained by texture softening. A good agreement was observed between the yield strength estimated as one-third of the hardness and the values calculated from the dislocation density, grain size and texture. The difference between the microstructure and hardness obtained for AM60 samples processed by HPT and equal channel angular pressing (ECAP) is discussed.
Permanent Link: http://hdl.handle.net/11104/0318049