Using ECAP to achieve grain refinement, precipitate fragmentation and high strain rate superplasticity in a spray-cast aluminum alloy

Xu, Cheng; Furukawa, Mutsuhisa; Horita, Zenji; Langdon, Terence G.

doi:10.1016/s1359-6454(03)00433-6

Cited by 234 publications

(149 citation statements)

References 42 publications

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“…In particular, a recent report described the fragmentation of the rod-like η-phase in an Al-7034 alloy during ECAP [7]. The present paper extends this work on the Al-7034 alloy by examining the evolution of the microstructure with consecutive passes through the ECAP die using differential scanning calorimetry (DSC) and electron back-scatter diffraction (EBSD) analysis.…”

Section: Introductionmentioning

confidence: 67%

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Microstructural evolution in a spray-cast aluminum alloy during equal-channel angular pressing

Gao

Starink

Furukawa

et al. 2005

Materials Science and Engineering: A

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A spray-cast Al-7034 alloy was processed by equal-channel angular pressing (ECAP) to a total of 8 passes at 473 K and the pressed samples were examined using transmission electron microscopy, differential scanning calorimetry and electron back-scatter diffraction. It is shown that the grain size of the alloy is reduced to ~0.3 μm by ECAP and the high pressures associated with ECAP lead to a fragmentation of the rod-like η-phase. The high temperature of ECAP also produces a precipitation of η-phase. There is an increase in the fraction of high-angle boundaries during the initial passes of ECAP but the fraction of low-angle boundaries remains high even after 8 passes.

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Section: Introductionmentioning

confidence: 67%

“…The experiments were conducted using a commercial Al-7034 alloy produced by spray-casting: the earlier report contained full details of the initial processing of the alloy [7].…”

Section: Experimental Materials and Proceduresmentioning

confidence: 99%

Microstructural evolution in a spray-cast aluminum alloy during equal-channel angular pressing

Gao

Starink

Furukawa

et al. 2005

Materials Science and Engineering: A

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“…10,11). Previous studies [17,40] on an overaged Al-Mg-Si alloy severely deformed by ECAP showed that rods of E' phase with 100-200 nm length were broken into small fragments having lengths of several tens of nanometers and also possibly partially dissolved. Such small precipitates are very useful in enhancing the thermal stability of these severely strained microstructures.…”

Section: Discussionmentioning

confidence: 96%

“…In particular, the observed strengthening of the as-cast sample is probably due to the presence of very fine precipitates along the grain boundaries which may act as strong pinning points and thus prevent grain growth or boundary sliding. By contrast, the HPT-induced dissolution of the nanoprecipitates that were initially present in the T6 peak-aged specimen favors the activation of GBS [17,26] and this produces a higher ductility and lower flow stress that may be useful for forming processes. It was reported earlier that the occurrence of GBS in an ultrafine grained Al-Zn alloys after HPT processing is favored by the presence of a solute-rich layer along the GBs [42,43].…”

Section: Discussionmentioning

confidence: 96%

“…For example, a yield strength of 1 GPa was achieved in an Al-Zn-Mg-Cu alloy processed by HPT [15]. Furthermore, it has been extensively reported [11,[16][17][18] that, since precipitates may contribute to greatly enhance the stability of the ultrafine-grained structures at high temperatures, SPDprocessed age-hardenable alloys are often capable of exhibiting superplastic properties when tested in tension after processing [17].…”

Section: Introductionmentioning

confidence: 99%

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Controlling the high temperature mechanical behavior of Al alloys by precipitation and severe straining

Cepeda-Jiménez

Castillo-Rodríguez

Molina-Aldareguia

et al. 2017

Materials Science and Engineering: A

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The aim of this work was to investigate the influence of the precipitate distribution on the microstructure and on the room and high temperature mechanical properties of an age-hardenable aluminium AA6082 alloy following severe straining by high-pressure torsion (HPT). With this goal, specimens in the as-cast and T6 peak-aged conditions were processed by HPT using 0.5, 1 and 5 turns at room temperature. At high strain levels (J>100), similar saturation grain sizes (~250 nm), high-angle boundary fractions (~80%) and hardness values (Hv~160) were obtained for both initial conditions. Grain refinement led to significant strengthening and to good ductility values at room temperature. Analysis by TEM and EDS elemental mapping revealed that HPT processing of the as-cast condition led to fracture of the stable E-phase into many small precipitates located preferentially along grain boundaries and triple junctions. By contrast, HPT processing of the T6 peak-aged specimens revealed a partial dissolution of the needle-shaped nanoprecipitates. The different evolutions of the precipitate distributions following straining in the as-cast and peak-aged conditions gave rise to dramatic differences in the mechanical properties and the operative deformation mechanisms at warm temperatures. These results provide evidence that the high temperature mechanical behavior of age-hardenable Al alloys may be conveniently controlled by altering the precipitate distribution followed by severe straining.

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Mechanical Properties at High Temperatures

Valiev¹,

Zhilyaev²,

Langdon³

2013

Bulk Nanostructured Materials

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Using ECAP to achieve grain refinement, precipitate fragmentation and high strain rate superplasticity in a spray-cast aluminum alloy

Cited by 234 publications

References 42 publications

Microstructural evolution in a spray-cast aluminum alloy during equal-channel angular pressing

Microstructural evolution in a spray-cast aluminum alloy during equal-channel angular pressing

Controlling the high temperature mechanical behavior of Al alloys by precipitation and severe straining

Mechanical Properties at High Temperatures

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