Structure uniformity and limits of grain refinement of high purity aluminum during multi-directional forging process at room temperature

Friction stir processing (FSP) is one of the severe plastic deformation (SPD) processes. It has been reported that SPD-processed Al with various purities attained a minimum grain size when Zener-Hollomon parameter is larger than 1016 s-1. The minimum grain size is different by purity level and alloying elements. We investigated the influence of Fe solute atoms on grain refinement of high-purity Al on the condition that Zener-Hollomon parameter was larger than 1016 s-1. FSP was conducted on Al-0.01%Fe, which was fabricated by using 5N Al (99.999% purity). FSP-ed Al-0.01%Fe exhibits the minimum grain size of 1.4 μm, although high-purity aluminums with more than 99.998% exhibits much larger minimum grain sizes of 30-40 μm. Only 101 at.ppm Fe played a critical role in the grain refinement of pure aluminums.

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The Structure Evolution of a 99.995 Percent High Purity Aluminum during Multi-Forging Process in Room Temperature

Materials Science Forum ◽

10.4028/www.scientific.net/msf.794-796.876 ◽

2014 ◽

Vol 794-796 ◽

pp. 876-881 ◽

Cited By ~ 6

Author(s):

Qing Feng Zhu ◽

Zhi Hao Zhao ◽

Yu Bo Zuo ◽

Lei Li ◽

Jian Zhong Cui

Keyword(s):

High Purity ◽

Deformation Zone ◽

Room Temperature ◽

True Strain ◽

Stagnant Zone ◽

Structure Evolution ◽

Cumulative Strain ◽

Aluminum Sample ◽

High Purity Aluminum ◽

Recrystallized Grain Size

In this study, a purity of 99.995percent high purity aluminum was multi-directionally forged up to a maximum cumulative strain of 4.5 at room temperature. The macro and micro structure evolution in the multi-directionally forge process was investigated by structure observations and hardness measurements. The results show that the inhomogeneous deformation of multi-directional forging results in that the structure and hardness is quite different between the easy deformation zone and stagnant zone. Dynamic recrystallization occurs in easy deformation zone of high purity aluminum sample at room temperature as the cumulative true strain is 1.5 (3 forging passes), while the structure in the stagnant zone is still not recrystallizated even at a cumulative true strain of 4.5 (9 forging passes). The recrystallized grain size in the easy deformation zone is reduced with the number of forging passes, and the area of recrystallize grains increase with the number of forging passes.

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Effect of Multi-Forging Condition on Deformed Structure and Mechanical Properties of A 99.995 Percent High Purity Aluminum

Materials Science Forum ◽

10.4028/www.scientific.net/msf.817.360 ◽

2015 ◽

Vol 817 ◽

pp. 360-366 ◽

Cited By ~ 2

Author(s):

Qing Feng Zhu ◽

Wen Jing Wang ◽

Zhi Hao Zhao ◽

Yu Bo Zuo ◽

Jian Zhong Cui

Keyword(s):

Mechanical Properties ◽

Mechanical Property ◽

High Purity ◽

Deformation Zone ◽

Room Temperature ◽

Stagnant Zone ◽

Water Cooling ◽

High Purity Aluminum

A purity of 99.995% high purity aluminum was deformed by multi-forging with different conditions (forged by different forging passes with and without water cooling). The effect of multi-forging on macrostructure and mechanical property of the high purity aluminum was investigated. The results show that the deformation heat during the MDF process can obviously affect the recrystallization of the high purity aluminum. Recrystallization occurs in the easy deformation zone of the sample as forged by 3 passes at room temperature. While, when the sample are cooling by water for each pass, no recrystallization occurs in the whole sample as forged by 9 passes. When the high purity forged at room temperature, the structure difference between the easy deformation zone and stagnant zone can not be eliminated by increasing the forging pass to 9. While, the area of the recrystal grain extends with increment of the forging pass.

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