Mechanical and Acoustic Emission Behavior of Mg-Li Based Alloys Compressed Before and After Pre-Deformation by Intensive Strain Methods
Archives of Current Research International · pp. 1–35 · Published 5 Sep 2017
10.9734/ACRI/2017/35252Abstract
The behavior of acoustic emission (AE) and its relationships with mechanisms of compression deformations of Mg-Li and Mg-Li-Al based alloys before and after the processing by intensive strain methods such as the ECAP (Equal Channel Angular Pressing) and the HPT (High Pressure Torsion) was examined. It was shown that the AE behaviour may be explained in terms of the collective, highly synchronized movements of the groups of many dislocations related to their acceleration as well as internal and surface annihilation. The intensity of AE in α single-phase of Mg-4Li based alloys is almost two orders of magnitude higher than that in pure Mg, and AE event rate reaches the maximum for Mg4Li alloy, what is imposed by the effect of Li addition, in leading to favoring of additional slip systems in prismatic and pyramidal planes. On the other hand the AE intensity in α+β two-phase of Mg-8Li based alloys rapidly decrease in comparison to that of single α phase. This is caused by very high diffusivity of lithium, which in consequence leading limitation the ability of dislocations to collective behavior. However, the AE intensity and activity in β single-phase of Mg-12Li based alloys is drastically low in comparison to α and α+β alloys. Two ranges of AE activity, observed in Mg12Li, is caused by high diffusivity of Li, which facilitating the processes of internal stress relaxation ensures generally high plasticity of β single-phase alloys. Moreover, the investigations of Mg9Li-Al based alloys have showed, that the AE increases together with the increase of Al concentration is the result of growing volume contribution of very efficient acoustically hexagonal α phase. The visible decrease of AE intensity and activity as well as increase in strength of alloys subjected to HPT and ECAP processing has been observed. Simultaneously the microstructure refinement of alloys after intensive strain processing was confirmed by electron (TEM) and optical microscopy technique. The possible explanation is discussed in terms of high increase of the density of immobile dislocations which strongly restrict ability to collective movement of source generate new dislocations. Also the hypothesis of possible contribution of slip along grain boundaries is discussed.
References (5)
- 1 Bulk nanostructured materials from severe plastic deformation [DOI]
- 2 Acoustic emission for physical examination of metals [DOI]
- 3 Density of kinks on a dislocation segment in thermodynamic equilibrium and the interaction between solitons [DOI]
- 4 Possibility of a soliton description of acoustic emission during plastic deformation of crystals [DOI]
- 5 Basic acoustic emission [DOI]
Cited by 1
Penchal Reddy Matli, Vyasaraj Manakari, Gururaj Parande · Materials Today: Proceedings · 2022
Related research
- Behaviour of Acoustic Emission in Deformation and Microcracking Processes of Mg Alloys Matrix Composites Subjected to Compression Tests — shares topic coverage
- Experimental Study on the Effect of Varying Cement Additive Percentages on the Mechanical Properties and Durability of Cement-Improved Loess — shares topic coverage
Article metrics
Real usage data collected on this platform.
0
Page views
0
PDF downloads
0
Outbound clicks
1
Citations
Views by country
Approximate, from request IP at view time — not citizenship or institution. Countries with fewer than 5 views are grouped as "Other".
No views recorded yet.
Traffic sources
Referring site, by host.
No traffic recorded yet.
Views and downloads exclude known bots/crawlers. Citations combines this platform's own DOI-resolved index with each external source's own reported total — see Cited by above for individually listed citing works. Last refreshed 0 seconds ago.