摘要
研究了稀土Gd的添加对铸态Mg-2Al-Zn合金显微组织和力学性能的影响。结果表明,Mg-2Al-Zn-xGd合金由α-Mg和Al2Gd两相组成,Al优先与Gd反应生成Al2Gd,且合金中Al2Gd的数量和形态受Gd的添加量影响。弥散分布的Al2Gd使合金室温力学性能得到显著提高,在Gd的添加量(质量分数)为2%时,抗拉强度和屈服强度分别达到252MPa和135MPa。但Gd的添加量达到3%时,Al2Gd相尺寸变大、数量过多,导致合金的力学性能迅速下降。颗粒状和针状Al2Gd在晶界上或基体上的团聚导致合金由韧性断裂转变为解理断裂。
Effects of Gd addition on the microstructure and mechanical properties of Mg-2Al-Zn magnesium alloy were investigated. The results reveal that the microstructure of as-cast Mg-2Al-Zn-xGd alloy is composed of α-Mg and Al2Gd phase formed by the prior reaction of Al and Gd. The amounts and morphology of Al2Gd phase are controlled by the Gd addition. Meanwhile, the dispersive Al2Gd phase had a positive contribution to greatly improve the mechanical properties of the alloy. The tensile strength and yield strength of the alloy are 252 MPa and 135 MPa respectively with 2% Gd addition, while the mechanical properties of the alloy can be obviously deteriorated as a result of the increase of the amount and size of Al2Gd phase with 3% Gd addition. The segregation of polygon and acicular Al2Gd particles in the boundary or the matrix can result in the change of fracture morphology from ductility fracture into cleavage fracture.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2007年第8期642-644,共3页
Special Casting & Nonferrous Alloys
基金
人事部高层次留学回国人员基金资助项目
