Effect of temperature and strain rate on the mechanisms of indentation deformation of magnesium

Haghshenas, M.; Bhakhri, Vineet; Oviasuyi, Richard O.; Klassen, Robert D.

doi:10.1557/mrc.2015.57

Cited by 10 publications

(3 citation statements)

References 16 publications

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“…[30] An analysis based on the total activation energy and activation volume indicates that screw dislocation cross-slip governs the operative plastic deformation of Mg, regardless of the strain rate and temperature (<300°C). [31] Nanoindentation experiments of high-purity Cr have also revealed the existence of thermally-activated strength component superimposed on a temperature-/rate-independent strength contribution, attributable to the propagation of screw dislocations governed by thermally-activated kink-pair nucleation. [32] Similarly, indentation plastic deformation of ultrafine-grained (UFG) Cu-Nb composite with a randomly distributed oriented grain size ∼100-200 nm up to 300°C is controlled by dislocation glide and nucleation of kink pairs.…”

Section: Plasticity Of Crystalline Materialsmentioning

confidence: 99%

Temperature-dependent nanoindentation response of materials

Chavoshi

2018

MRS Communications

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Section: Plasticity Of Crystalline Materialsmentioning

confidence: 99%

Temperature-dependent nanoindentation response of materials

Chavoshi

2018

MRS Communications

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“…For example, Somekawa and Schuh [18] and Haghshenas et al [19] used nano-and micro-indentation tests at high (150 s −1 ) and low (10 −5 -10 −1 s −1 ) strain rates, respectively, to investigate the creep response of pure Mg at room and elevated temperatures. Through activation energy calculations, the studies have attributed dislocation slip and twinning to be the two dominant mechanisms controlling indentation creep of pure Mg. Haghshenas et al [19] in particular, showed that these deformation mechanisms are operative and dominant over not only the aforementioned wide strain rate range, but also across a wide temperature range (295-573 K). Despite the well-documented creep behavior of pure Mg, the creep response and deformation mechanisms behind Mg-CNT nanocomposites remain a virgin field.…”

Section: Introductionmentioning

confidence: 99%

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

Thornby

Verma²,

Mullis

et al. 2019

SN Appl. Sci.

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The time-dependent plastic deformation response of magnesium/carbon nanotube (CNT) nanocomposites containing 0.25, 0.5, and 0.75 vol% of carbon nanotubes is investigated through depth nanoindentation tests against monolithic pure magnesium in the present study. The Mg-CNT nanocomposite materials were successfully synthesized via a powder metallurgy technique coupled with microwave sintering followed by hot extrusion to produce 8-mm diameter, long solid bars. All depth-sensing indentation creep tests were conducted at ambient (room) temperature employing a diamond Berkovich pyramidal indenter. These tests are dual-stage, i.e., loading to a prescribed peak load of 50 mN, holding the peak load constant for a dwell period of 500 s, and finally unloading. Various strain rates of 0.01, 0.1, 1, and 10 s −1 were performed to assess the effects of strain rate and dwell time on the ambient temperature creep response of the Mg-CNT nanocomposites. The outcomes of these tests are explained through material hardness, microstructure, the extent of CNT content in each material, and strain rate sensitivity. Upon analyzing the nanoindentation creep tests, the dominant creep mechanism at room temperature was found to be a dislocation creep mechanism. It is also found that CNTs increase the creep resistance of magnesium. Findings of this study can be used as a starting point for a high-temperature creep study on Mg-CNT nanocomposites. This paper is a continued study from our group on time-dependent plastic deformation of Mg nanocomposites (i.e., see Haghshenas et al., Journal of Composite Materials,

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“…This technique can also be used to probe localized features, like an individual grain and grain boundary, which is not possible by conventional creep tests. 15–19 In particular, we are interested in studying the effect of varying volume fractions of nano-BN addition on the ambient-temperature rate dependent plastic deformation (creep) responses and comparing them against pure Mg. The ambient temperature creep mechanisms of the Mg/BN nanocomposite materials need to be documented as the baselines for studying the elevated-temperature creep.…”

Section: Introductionmentioning

confidence: 99%

Depth sensing indentation of magnesium/boron nitride nanocomposites

Haghshenas

Islam

Wang

et al. 2018

Journal of Composite Materials

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Magnesium nanocomposites, considered as energy-saving lightweight materials of future, are a fairly new family of composite materials with enhanced specific strength and ductility compared to pure magnesium and/or magnesium alloys. In the present study, time-dependent plastic deformation of novel light-weight magnesium/boron nitride nanocomposites containing 0.5, 1.5 and 2.5 vol% of nano-boron nitride particulates is studied through a depth-sensing indentation approach against monolithic pure magnesium. The synthesis of magnesium–boron nitride nanocomposites was accomplished using powder metallurgy technique coupled with microwave sintering, followed by hot extrusion (end products are 8-mm diameter rods). The depth sensing indentation creep tests were conducted at room temperature (∼0.32Tm of magnesium) using an instrumented indentation platform via a self-similar pyramidal (Berkovich) indenter. To assess the influence of loading rate on the indentation-induced deformation behavior of the materials, a dual stage indentation creep including a constant loading rate followed by a constant load-holding scheme was used; indentation tests were performed on the specimens. The specimens were loaded at rates of 0.05, 0.5, 5, and 50 mN/s to a peak load of 50 mN then force was held constant for 400 s while load/displacement/time data were recorded continuously. The results of the depth sensing indentation tests were correlated and explained using the microstructural characteristics placing special emphasis on the volume fraction of reinforcement and the indentation loading rate. Finally, the controlling creep mechanisms of the magnesium–boron nitride nanocomposites and the base metal (pure magnesium) were discussed in the present paper. The results of this paper can be used as a baseline for high-temperature creep analysis of magnesium–boron nitride nanocomposites which is of engineering significance.

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Effect of temperature and strain rate on the mechanisms of indentation deformation of magnesium

Abstract: Abstract

Cited by 10 publications

References 16 publications

Temperature-dependent nanoindentation response of materials

Temperature-dependent nanoindentation response of materials

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

Depth sensing indentation of magnesium/boron nitride nanocomposites

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