Effect of primary crystals on pore morphology during semi-solid foaming of A2024 alloys

Takashi Kuwahara, Mizuki Saito, Taro Osaka, Shinsuke Suzuki

Research output: Contribution to journalArticle

Abstract

We investigated pore formation in aluminum foams by controlling primary crystal morphology using three master alloys. The first one was a direct chill cast A2024 (Al-Cu-Mg) alloy (DC-cast alloy). The others were A2024 alloys prepared to possess fine spherical primary crystals. The second alloy was made by applying compressive strain through a Strain-Induced Melt-Activated process alloy (SIMA alloy). The third one was a slope-cast A2024 alloy (slope-cast alloy). Each alloy was heated to either 635C (fraction of solid fs = 20%) or 630C (fs = 40%). TiH2 powder was added to the alloys as a foaming agent upon heating them to a semi-solid state and they were stirred while being held in the furnace. Subsequently, A2024 alloy foams were obtained via water-cooling. The primary crystals of the DC-cast alloy were coarse and irregular before foaming. After foaming, the size of the primary crystals remained irregular, but also became spherical. The SIMA and slope-cast alloys possessed fine spherical primary crystals before and after foaming. In addition to average-sized pores (macro-pores), small pores were observed inside the cell walls (micro-pores) of each alloy. The formation of macro-pores did not depend on the formation of the primary crystals. Only in the DC-cast alloy did fine micro-pores exist within the primary crystals. The number of micro-pores in the SIMA and slope-cast alloys was one third of that in the DC-cast alloy.

LanguageEnglish
Article number88
JournalMetals
Volume9
Issue number1
DOIs
Publication statusPublished - 2019 Jan 1

Fingerprint

Crystals
Macros
Foams
Blowing agents
Cooling water
Aluminum
Powders
Furnaces
Cells
Heating

Keywords

  • Aluminum foam
  • Pore morphology
  • Primary crystals
  • Semi-solid
  • SIMA process
  • Slope casting

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Effect of primary crystals on pore morphology during semi-solid foaming of A2024 alloys. / Kuwahara, Takashi; Saito, Mizuki; Osaka, Taro; Suzuki, Shinsuke.

In: Metals, Vol. 9, No. 1, 88, 01.01.2019.

Research output: Contribution to journalArticle

Kuwahara, Takashi ; Saito, Mizuki ; Osaka, Taro ; Suzuki, Shinsuke. / Effect of primary crystals on pore morphology during semi-solid foaming of A2024 alloys. In: Metals. 2019 ; Vol. 9, No. 1.
@article{925b54fb3a5c43348daafe41268693f3,
title = "Effect of primary crystals on pore morphology during semi-solid foaming of A2024 alloys",
abstract = "We investigated pore formation in aluminum foams by controlling primary crystal morphology using three master alloys. The first one was a direct chill cast A2024 (Al-Cu-Mg) alloy (DC-cast alloy). The others were A2024 alloys prepared to possess fine spherical primary crystals. The second alloy was made by applying compressive strain through a Strain-Induced Melt-Activated process alloy (SIMA alloy). The third one was a slope-cast A2024 alloy (slope-cast alloy). Each alloy was heated to either 635◦C (fraction of solid fs = 20{\%}) or 630◦C (fs = 40{\%}). TiH2 powder was added to the alloys as a foaming agent upon heating them to a semi-solid state and they were stirred while being held in the furnace. Subsequently, A2024 alloy foams were obtained via water-cooling. The primary crystals of the DC-cast alloy were coarse and irregular before foaming. After foaming, the size of the primary crystals remained irregular, but also became spherical. The SIMA and slope-cast alloys possessed fine spherical primary crystals before and after foaming. In addition to average-sized pores (macro-pores), small pores were observed inside the cell walls (micro-pores) of each alloy. The formation of macro-pores did not depend on the formation of the primary crystals. Only in the DC-cast alloy did fine micro-pores exist within the primary crystals. The number of micro-pores in the SIMA and slope-cast alloys was one third of that in the DC-cast alloy.",
keywords = "Aluminum foam, Pore morphology, Primary crystals, Semi-solid, SIMA process, Slope casting",
author = "Takashi Kuwahara and Mizuki Saito and Taro Osaka and Shinsuke Suzuki",
year = "2019",
month = "1",
day = "1",
doi = "10.3390/met9010088",
language = "English",
volume = "9",
journal = "Metals",
issn = "2075-4701",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "1",

}

TY - JOUR

T1 - Effect of primary crystals on pore morphology during semi-solid foaming of A2024 alloys

AU - Kuwahara, Takashi

AU - Saito, Mizuki

AU - Osaka, Taro

AU - Suzuki, Shinsuke

PY - 2019/1/1

Y1 - 2019/1/1

N2 - We investigated pore formation in aluminum foams by controlling primary crystal morphology using three master alloys. The first one was a direct chill cast A2024 (Al-Cu-Mg) alloy (DC-cast alloy). The others were A2024 alloys prepared to possess fine spherical primary crystals. The second alloy was made by applying compressive strain through a Strain-Induced Melt-Activated process alloy (SIMA alloy). The third one was a slope-cast A2024 alloy (slope-cast alloy). Each alloy was heated to either 635◦C (fraction of solid fs = 20%) or 630◦C (fs = 40%). TiH2 powder was added to the alloys as a foaming agent upon heating them to a semi-solid state and they were stirred while being held in the furnace. Subsequently, A2024 alloy foams were obtained via water-cooling. The primary crystals of the DC-cast alloy were coarse and irregular before foaming. After foaming, the size of the primary crystals remained irregular, but also became spherical. The SIMA and slope-cast alloys possessed fine spherical primary crystals before and after foaming. In addition to average-sized pores (macro-pores), small pores were observed inside the cell walls (micro-pores) of each alloy. The formation of macro-pores did not depend on the formation of the primary crystals. Only in the DC-cast alloy did fine micro-pores exist within the primary crystals. The number of micro-pores in the SIMA and slope-cast alloys was one third of that in the DC-cast alloy.

AB - We investigated pore formation in aluminum foams by controlling primary crystal morphology using three master alloys. The first one was a direct chill cast A2024 (Al-Cu-Mg) alloy (DC-cast alloy). The others were A2024 alloys prepared to possess fine spherical primary crystals. The second alloy was made by applying compressive strain through a Strain-Induced Melt-Activated process alloy (SIMA alloy). The third one was a slope-cast A2024 alloy (slope-cast alloy). Each alloy was heated to either 635◦C (fraction of solid fs = 20%) or 630◦C (fs = 40%). TiH2 powder was added to the alloys as a foaming agent upon heating them to a semi-solid state and they were stirred while being held in the furnace. Subsequently, A2024 alloy foams were obtained via water-cooling. The primary crystals of the DC-cast alloy were coarse and irregular before foaming. After foaming, the size of the primary crystals remained irregular, but also became spherical. The SIMA and slope-cast alloys possessed fine spherical primary crystals before and after foaming. In addition to average-sized pores (macro-pores), small pores were observed inside the cell walls (micro-pores) of each alloy. The formation of macro-pores did not depend on the formation of the primary crystals. Only in the DC-cast alloy did fine micro-pores exist within the primary crystals. The number of micro-pores in the SIMA and slope-cast alloys was one third of that in the DC-cast alloy.

KW - Aluminum foam

KW - Pore morphology

KW - Primary crystals

KW - Semi-solid

KW - SIMA process

KW - Slope casting

UR - http://www.scopus.com/inward/record.url?scp=85060348221&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060348221&partnerID=8YFLogxK

U2 - 10.3390/met9010088

DO - 10.3390/met9010088

M3 - Article

VL - 9

JO - Metals

T2 - Metals

JF - Metals

SN - 2075-4701

IS - 1

M1 - 88

ER -