Effect of Zr Addition on Dynamic Recrystallization during Hot Extrusion in Al Alloys

Adachi, Hiroki; Osamura, Kōzō; Kikuchi, Ken; Kusui, Jun

doi:10.2320/matertrans.46.211

Cited by 15 publications

(7 citation statements)

References 16 publications

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“…In the extruded alloys, the number of fine grains is constant, such as, independent of the amount of Zr addition. In Meso10-Zr, the number of fine grains increases with the amount of Zr addition [4]. This means that Zr addition might not promote DRX in Meso10-4Mn-Zr.…”

Section: Resultsmentioning

confidence: 94%

Effect of multiple additives (Mn and Zr) on microstructure of P/M 7000 series aluminum alloys

Yamamoto

Adachi

Morimoto

et al. 2009

Trans Indian Inst Met

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Mesoalite series alloys were formed using rapid solidification powder metallurgy (RS-P/M) by hot extrusion. The addition of Mn and Zr to the basic Mesoalite alloy (Meso10) in excess led to continuous dynamic recrystallization (DRX) in the alloy during hot extrusion through a different mechanism. In order to achieve a synergistic effect, Mn and Zr additives were used simultaneously. It was found that the DRX mechanism was governed by the addition of Mn, while the Zr addition was effective in coarsening control.

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Section: Resultsmentioning

confidence: 94%

Effect of multiple additives (Mn and Zr) on microstructure of P/M 7000 series aluminum alloys

Yamamoto

Adachi

Morimoto

et al. 2009

Trans Indian Inst Met

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“…The melting temperature of this phase is 1,350℃ and it prevents the grain boundary from migrating so to maintain the grain size constant during superplastic forming process. This phase is known to inhibit recrystallization of aluminum alloy at elevated temperature [7]. The gas pressure profile obtained from the analysis was employed in the superplastic forming process as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

An Experimental Study on Superplastic Hemispherical Forming of Aluminum Lithium 2195 Alloy

Lee¹,

Yoo²

2018

IJMMM

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Abstract-Superplastic forming (SPF) technology is currently being used to produce a number of components for aerospace vehicles. The most important advantages of using SPF technology is the process simplicity and economy in tooling. The widely used superplastic materials are titanium alloys and aluminum alloys, which are the workhorse alloys of the aerospace industry. The low density and good mechanical properties of Aluminum-Lithium 2195 alloy make them successfully used in cryogenic tank of space vehicles. In this study, a hemispherical dome is produced with this alloy by superplastic forming. By controlling hydraulic gas pressure, it was possible to maintain the superplastic condition during the forming process. The forming temperature was 460℃ to form a complete hemispherical dome with diameter of 350 mm for 3,420 sec. The programmed gas pressure was applied and the maximum pressure was limited to 5 MPa to protect the forming tool. The distribution of thickness within the hemisphere was investigated and confirmed the analysis result. The process development for the production of a hemisphere with 2195 aluminum alloy has been achieved. The hemispherical dome is in good conformity with drawing dimensional and tolerance specifications.Index Terms-Aluminum lithium alloy, gas pressure forming, hemisphere, superplastic forming.

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“…It is thought that L1 2 -structured Al 3 Zr particles precipitate upon the addition of 1.3 mass% Zr during the degassing process before hot extrusion, and that these particles inhibit the migration of initial grains [3,4]. Hot extrusion resulted in high-density dislocations in the inhomogeneous deformation region near the initial grain Keywords: aluminium alloy; Al 3 Sc; dynamic recrystallisation boundaries.…”

Section: Introductionmentioning

confidence: 98%

Effect of dispersed Al3Sc particles on dynamic recrystallization in P/M 7000 series alloys

Adachi

Yammoto

Nakanishi

et al. 2009

Trans Indian Inst Met

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Al 3 Sc particles are well known to be a recrystallization inhibitor in Al alloys. In this study, 0.4, 0.8 and 1.5 mass% Sc were added to 7000 series Al alloys in supersaturation by using powder metallurgy. By subjecting rapidly solidified powders of these alloys to a heat treatment at 773 K, Al 3 Sc particles were precipitated in the matrix. Subsequently, hot extrusion was carried out at 773 K. During extrusion, continuous dynamic recrystallization (DRX) occurred and fine DRX grains with a diameter of 1 mm were formed. The number of DRX grains was the largest in the 1.5Sc alloy. Even though the amount of Sc added in this case was two times larger, the number of DRX grains in 0.4Sc was almost the same as that in 0.8Sc. Since continuous DRX occurs only under conditions where the grain boundary mobility is low, the number of DRX grains is strongly related to the pinning force on the initial grain boundary exerted by Al 3 Sc particles. The pinning force varied with the diameter and volume fraction of Al 3 Sc particles. When the pinning force was calculated from the diameter of Al 3 Sc particles, which was measured by TEM, it was proven that the number of DRX grains was proportional to the calculated pinning force. Except in the case of 0.4Sc, the Al 3 Sc particle diameter was twice that obtained at the maximum pinning force (d max ). It is possible to promote continuous DRX by decreasing the Al 3 Sc particle diameter in 0.8 and 1.5Sc alloys. Lowering the heating rate before heat treatment for degassing reduced the critical nucleus size for precipitation of Al 3 Sc particles as well the diameter of Al 3 Sc particles. Thus, the pinning force increased in 0.8Sc and 1.5Sc alloys, and the number of DRX grains also increased, as expected.

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Effect of Zr Addition on Dynamic Recrystallization during Hot Extrusion in Al Alloys

Cited by 15 publications

References 16 publications

Effect of multiple additives (Mn and Zr) on microstructure of P/M 7000 series aluminum alloys

Effect of multiple additives (Mn and Zr) on microstructure of P/M 7000 series aluminum alloys

An Experimental Study on Superplastic Hemispherical Forming of Aluminum Lithium 2195 Alloy

Effect of dispersed Al3Sc particles on dynamic recrystallization in P/M 7000 series alloys

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