Effect of Solidified Structure on Hot Tearing in Al-Cu Alloy

Abstract:

Hot tearing is the one of the biggest problems when casting aluminium alloys. Although there has been much research work in this field, it is still not clear what causes hot tearing and how it propagates. Furthermore, the effect of solidified structure on the hot tearing has not been clear. Therefore, this study has been carried out to correlate the solidified structure and hot tearing. Al-2.0 wt% Cu alloy was used for test alloy. To change the solidified structure, some amount of refiner was added to the molten alloy. A permanent mould, which has been developed by us, can form hot tearing intentionally in the center region of a solidified shell. The cross section of a solidified shell was metallographically investigated and solidified structure and hot tearing were characterized. The length of hot tear decreased with increasing the amount of refiner. This may indicate that it is difficult for hot tear with fine equiaxed grains to propagate. In addition to this, the residual liquid around the hot tear was moved to the cracking due to negative pressure and hot tearing was partially healed.

• Periodical: Materials Science Forum (Volumes 828-829)
• Pages: 58-61
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.828-829.58
• Online since: August 2015
• Authors: Yasuyuki Yoshida, Hisao Esaka, Kei Shinozuka
• Keywords: Al-Cu, Divorced Eutectic Structure, Eutectic Structure, Healing, Hot Tear

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