The Mg-8Gd-3Y-0.5Zr（GW83）alloy was fabricated by semi-continuous casting.The mechanical properties of peak-aged alloy at room and elevated temperatures as well as compressive creep properties at 300 ℃ were investigated.The results reveal that precipitates in grain are uniformly distributed in the alloy after solution treatment at 500 ℃ for 4hand subsequent ageing at 225 ℃ for 15 h

and the peak-aged alloy exhibits prominent mechanical properties with a tensile strength and elongation of 363 MPa and 5.8%

respectively.However

the tensile strength of T6 treated alloy is decreased with the increase of temperature

and the tensile strength is decreased sharply to 219 MPa

while the elongation is increased to 20.7% at 300℃.The peak-aged alloy also exhibits desirable creep resistance at 300℃and stresses in range of 50

1

20 MPa.The measured creep exponent is 3.36

suggesting that dislocation sliding is the dominant creep mechanism at the test conditions