TY - CHAP

T1 - Quantitative determination on hot tearing in Mg-Al binary alloys

AU - Zhen, Zisheng

AU - Hort, Norbert

AU - Huang, Yuanding

AU - Petri, Nicolai

AU - Utke, Oliver

AU - Kainer, Karl U.

N1 - Conference code: 4

PY - 2009

Y1 - 2009

N2 - Hot tearing, or hot cracking, is one of the most severe solidification defects commonly encountered during casting. It is such a complicated phenomenon that a full understanding is still not yet achieved, though it has been extensively investigated for decades. Most contributions are still based on qualitative characterisations. The purpose of this work is to develop a method that can quantitatively evaluate and investigate hot tearing behaviour. The principle is based on contraction stress/force measurements. The measured contraction force has been proven to be able to evaluate the hot tearing susceptibility as a more straightforward and quantitative index. By analyzing the contraction force curve, information can be obtained for both the initiation and the propagation of the hot tear. With this method, the influence of mould temperature and Al content on hot tearing behaviour of Mg-Al binary alloys has been investigated. The contraction force curves also indicate that the liquid refilling plays an important role during the hot crack propagation. With a lower cooling rate and higher onset temperature of hot tear, the remaining liquid is more favourable to refill the initiated hot crack, and consequently interrupts the propagation of cracks or possibly completely heals the cracks.

AB - Hot tearing, or hot cracking, is one of the most severe solidification defects commonly encountered during casting. It is such a complicated phenomenon that a full understanding is still not yet achieved, though it has been extensively investigated for decades. Most contributions are still based on qualitative characterisations. The purpose of this work is to develop a method that can quantitatively evaluate and investigate hot tearing behaviour. The principle is based on contraction stress/force measurements. The measured contraction force has been proven to be able to evaluate the hot tearing susceptibility as a more straightforward and quantitative index. By analyzing the contraction force curve, information can be obtained for both the initiation and the propagation of the hot tear. With this method, the influence of mould temperature and Al content on hot tearing behaviour of Mg-Al binary alloys has been investigated. The contraction force curves also indicate that the liquid refilling plays an important role during the hot crack propagation. With a lower cooling rate and higher onset temperature of hot tear, the remaining liquid is more favourable to refill the initiated hot crack, and consequently interrupts the propagation of cracks or possibly completely heals the cracks.

KW - Castability

KW - Crack formation

KW - Hot tearing

KW - Magnesium alloys

KW - Solidification

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=70349513667&partnerID=8YFLogxK

U2 - 10.4028/www.scientific.net/MSF.618-619.533

DO - 10.4028/www.scientific.net/MSF.618-619.533

M3 - Article in conference proceedings

AN - SCOPUS:70349513667

SN - 0878493271

SN - 9780878493272

T3 - Materials Science Forum

SP - 533

EP - 540

BT - 4th International Conference Organised by the CAST CRC, on Behalf of the Global Light Metals Alliance

A2 - Dargusch, M. S.

A2 - Keay, S. M.

PB - Trans Tech Publications Ltd

T2 - 4th International Conference Organised by the CAST CRC, on Behalf of the Global Light Metals Alliance 2009

Y2 - 29 June 2009 through 1 July 2009

ER -