TY - JOUR

T1 - Effects of Sn segregation and precipitates on creep response of Mg-Sn alloys

AU - Huang, Y.

AU - Dieringa, H.

AU - Kainer, K. U.

AU - Hort, N.

PY - 2013/4

Y1 - 2013/4

N2 - Mg-Sn alloys are promising for the development of new cheap creep resistant magnesium alloys. In the present paper, the creep behaviours of Mg-Sn and Mg-Sn-Ca alloys were examined at the constant temperature and different stresses. The measurements of stress exponents indicate that the dislocation climbing is the dominant mechanism during the creep of Mg-3Sn or Mg-3Sn-2Ca alloys. The poor creep resistance of the binary Mg-3Sn alloy is caused by the easy movement of dislocation and the segregation of Sn at the boundaries. Both T4 and T6 heat treatments improve the creep resistance of Mg-3Sn alloy due to the alleviation of Sn segregation at grain boundaries and the precipitation of Mg2Sn particles, respectively. Ca is an effective alloying element to increase the creep resistance of Mg-Sn alloys. The Ca addition leads to the formation of thermal stable phases Mg2Ca and CaMgSn in Mg-3Sn-Ca alloys. These two phases effectively hinder the movement of dislocations and the sliding of grain boundaries. On the other hand, the addition of Ca alleviates the segregation of Sn by the interaction of Ca with Mg and Sn to form the phase CaMgSn.

AB - Mg-Sn alloys are promising for the development of new cheap creep resistant magnesium alloys. In the present paper, the creep behaviours of Mg-Sn and Mg-Sn-Ca alloys were examined at the constant temperature and different stresses. The measurements of stress exponents indicate that the dislocation climbing is the dominant mechanism during the creep of Mg-3Sn or Mg-3Sn-2Ca alloys. The poor creep resistance of the binary Mg-3Sn alloy is caused by the easy movement of dislocation and the segregation of Sn at the boundaries. Both T4 and T6 heat treatments improve the creep resistance of Mg-3Sn alloy due to the alleviation of Sn segregation at grain boundaries and the precipitation of Mg2Sn particles, respectively. Ca is an effective alloying element to increase the creep resistance of Mg-Sn alloys. The Ca addition leads to the formation of thermal stable phases Mg2Ca and CaMgSn in Mg-3Sn-Ca alloys. These two phases effectively hinder the movement of dislocations and the sliding of grain boundaries. On the other hand, the addition of Ca alleviates the segregation of Sn by the interaction of Ca with Mg and Sn to form the phase CaMgSn.

KW - creep

KW - magnesium

KW - magnesium-tin alloys

KW - microstructure

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=84875152679&partnerID=8YFLogxK

U2 - 10.1111/ffe.12000

DO - 10.1111/ffe.12000

M3 - Journal articles

AN - SCOPUS:84875152679

VL - 36

SP - 308

EP - 315

JO - Fatigue and Fracture of Engineering Materials and Structures

JF - Fatigue and Fracture of Engineering Materials and Structures

SN - 8756-758X

IS - 4

ER -