Tensile behavior of bulk nanocrystalline aluminum synthesized by hot extrusion of ball-milled powders

Choi, Hyunjoo; Lee, S.W.; Park, J.S.; Bae, D.H.

doi:10.1016/j.scriptamat.2008.07.030

Cited by 77 publications

(39 citation statements)

References 16 publications

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“…In Fig. 5, yield stresses of aluminums, presented in this study and reported in other literatures [22,24,[27][28][29], are plotted as a function of grain size (d −1/2 ). Furthermore, calculated yield stresses based on the Hall-Petch equation [2], the deformation twin [13], the emission of partial and perfect dislocations [11], and grain boundary sliding [30] are also included.…”

Section: Resultsmentioning

confidence: 81%

“…Compared to the pattern of the starting powders, the ball-milled samples showed broadened peaks, indicating that grain size is effectively reduced during ball milling. The recognition of grain growth occurred when the sample was exposed to high temperatures for a long period [24], and the condensed green compact was heated to the target temperature with a high average heating rate of ∼20…”

Section: Methodsmentioning

confidence: 99%

“…However, an experimental study using an extruded NC aluminum bulk has reported results that are completely opposite to a positive deviation from the Hall-Petch relation [22]. Recently, UFC aluminum fabricated by accumulative roll bonding has exhibited limited uniform elongation and unexpected yield-drop-like phenomenon [23], while it has not been observed in UFC aluminum having undergone powder metallurgy with similar grain sizes [24].…”

Section: Introductionmentioning

confidence: 99%

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The Effect Of Grain Size On The Mechanical Properties Of Aluminum

Jeong¹,

Park²,

Nam³

et al. 2015

Archives of Metallurgy and Materials

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Although many studies have focused on the unique plastic deformation behavior of nanocrystalline aluminum (e.g., the positive deviation from Hall-Petch relation, the unusual yield-drop phenomenon in tensile mode, etc.), the data reported by different research groups are inconsistent with each other, possibly because of different fabrication processes. In this study, aluminum samples with a wide grain-size spectrum -from a few micrometers down to 100 nanometers -are manufactured by powder metallurgy. The grain size was measured by X-ray diffraction analysis and transmission electron microscope observation. Furthermore, the tensile behavior, which varied according to a grain size, is discussed with a comparison of the theoretical models.

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Section: Resultsmentioning

confidence: 81%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Effect Of Grain Size On The Mechanical Properties Of Aluminum

Jeong¹,

Park²,

Nam³

et al. 2015

Archives of Metallurgy and Materials

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show abstract

“…In addition, the average grain size was also evaluated by an X-ray diffraction (XRD) method when the grain size was less than 100 nm. The average grain size d can be expressed as [17] …”

Section: Methodsmentioning

confidence: 99%

“…Choi et al [17] studied the tensile behaviour of bulk nanocrystalline aluminium synthesised by the hot extrusion of ballmilled powders and ascertained that the aluminium powders milled for 48 h with an average grain size of 48 nm had a superior yield stress of 500 MPa with ductile fracture. The most interesting finding to date has been from Poirier and his colleagues; they investigated the yield strength of hotpressed ball-milled aluminium powders and determined that milled pure aluminium powders with an average grain size of 60 nm had average yield strength of 592 MPa [6].…”

Section: Related Workmentioning

confidence: 99%

Characterisation and milling time optimisation of nanocrystalline aluminium powder for selective laser melting

Han

Setchi

Evans

2016

Int J Adv Manuf Technol

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The aim of this study is to investigate the properties of high-energy ball-milled nanocrystalline aluminium powders and to determine the optimum milling time required to produce an advanced aluminium powder for selective laser melting (SLM). Previous research has indicated that powders suitable for SLM include milled nanocrystalline aluminium powders with an average grain size of 60 nm and good flowability (Carr index less than 15 %). This study employs advanced nanometrology methods and analytical techniques to investigate the powder morphology, phase identification, average grain size and flowability of ball-milled powders. Stearic acid is used to prevent excessive cold welding of the ball-milled powder and to reduce abrasion of the grinding bowl and balls. The results indicate that, whilst the average particle size achieves a steady state after 14 h of milling, the grain size continues to decrease as the milling time progressed (e.g. the transmission electron microscopy measured average grain size is 56 nm after 20 h of milling compared to 75 nm for 14 h of milling). The aluminium powders milled for 16 and 20 h exhibit good flow behaviour, achieving a Carr index of 13.5 and 15.8 %, respectively. This study shows that advanced nanocrystalline aluminium powders suitable for SLM require ball milling for between 16 and 20 h, with 18 h being the optimum milling time.

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Preparation of Nanocrystalline Aluminum by Warm‐Vacuum‐Compaction Method

Liu

Zhou

2011

Supplemental Proceedings

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Tensile behavior of bulk nanocrystalline aluminum synthesized by hot extrusion of ball-milled powders

Cited by 77 publications

References 16 publications

The Effect Of Grain Size On The Mechanical Properties Of Aluminum

The Effect Of Grain Size On The Mechanical Properties Of Aluminum

Characterisation and milling time optimisation of nanocrystalline aluminium powder for selective laser melting

Preparation of Nanocrystalline Aluminum by Warm‐Vacuum‐Compaction Method

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