TY - CHAP

T1 - Investigations on hot tearing of Mg-Al binary alloys by using a new quantitative method

AU - Zhen, Zisheng

AU - Hort, Norbert

AU - Utke, Oliver

AU - Huang, Yuanding

AU - Petri, Nikoli

AU - Kainer, Karl Ulrich

PY - 2009

Y1 - 2009

N2 - Hot tearing, also referred as hot cracking, is a commonly encountered solidification defect during castings. Although it has been extensively investigated for decades, most contributions are still based on qualitative characterizations. In this work, a quantitative method to investigate hot tearing has been developed, based on the measurement of contraction force. The advantage of the present evaluation system, which is mainly different from previous apparatus, is to eliminate the influence of friction between the mould and casting rod., The results obtained using this system demonstrate good repeatability and reliability. The measured contraction force has been proved to be able to evaluate the ho1: tearing susceptibility as a more straightforward and quantitative index. By analyzing the contraction force curve, both the initiation and propagation of hot tear can be detected. With this method, the hot tearing of Mg-Al binary alloys has been investigated. The results show that increasing the mould temperature decreases the hot tearing susceptibility, meanwhile increases the temperature of the hot tearing initiation. The contraction force curves also indicate that the liquid refilling plays an important role in the formation of hot tearing. With a lower cooling rate, the remained liquid possibly refills the initiated hot crack, and consequently partially or completely heals the cracks.

AB - Hot tearing, also referred as hot cracking, is a commonly encountered solidification defect during castings. Although it has been extensively investigated for decades, most contributions are still based on qualitative characterizations. In this work, a quantitative method to investigate hot tearing has been developed, based on the measurement of contraction force. The advantage of the present evaluation system, which is mainly different from previous apparatus, is to eliminate the influence of friction between the mould and casting rod., The results obtained using this system demonstrate good repeatability and reliability. The measured contraction force has been proved to be able to evaluate the ho1: tearing susceptibility as a more straightforward and quantitative index. By analyzing the contraction force curve, both the initiation and propagation of hot tear can be detected. With this method, the hot tearing of Mg-Al binary alloys has been investigated. The results show that increasing the mould temperature decreases the hot tearing susceptibility, meanwhile increases the temperature of the hot tearing initiation. The contraction force curves also indicate that the liquid refilling plays an important role in the formation of hot tearing. With a lower cooling rate, the remained liquid possibly refills the initiated hot crack, and consequently partially or completely heals the cracks.

KW - Castability

KW - Crack formation

KW - Hot tearing

KW - Magnesium alloys

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=70349519098&partnerID=8YFLogxK

M3 - Article in conference proceedings

AN - SCOPUS:70349519098

SN - 9780873397308

SN - 0873397304

T3 - Magnesium Technology

SP - 105

EP - 110

BT - Magnesium Technology 2009

A2 - Nyberg, Eric A.

A2 - Agnew, Sean R.

A2 - Neelameggham, Neale R.

A2 - Pekguleryuz, Mihriban O.

PB - John Wiley & Sons Inc.

T2 - Magnesium Technology 2009

Y2 - 15 February 2009 through 19 February 2009

ER -