Sr对AZ81镁合金β-Mg_(17)Al_(12)析出相形态及力学性能的影响  

Effect of Sr on Morphology of β-Mg_(17)Al_(12) Precipitated Phase and Mechanical Properties of AZ81 Magnesium Alloy

作　　者：马先臻[1] 许春香[1] 程伟丽[1] 张文波[1] 

机构地区：[1]太原理工大学材料科学与工程学院,山西太原030024

出　　处：《铸造》2013年第3期230-234,共5页Foundry

基　　金：山西省自然科学基金资助项目(2012011022-1)

摘　　要：采用OM、XRD、SEM、EDS和电子拉伸试验机研究了Sr对AZ81镁合金β-Mg17Al12析出相形态及力学性能的影响。结果表明,加入0.3%的Sr时,合金中β-Mg17Al12相得到了明显细化,合金中出现颗粒状及杆状Al4Sr新相。随着Sr含量增加,β-Mg17Al12相从连续网状变为不连续网状和块状,且合金常温力学性能在Sr含量为0.6%时达到最高。当Sr含量到0.9%时,β-Mg17Al12相数量进一步减少,Al4Sr相偏聚呈断续网状。AZ81-xSr镁合金经过T6处理后,在α-Mg相晶界及晶内析出了大量层片状或针状、点状β-Mg17Al12相,合金力学性能得到显著提高。随着Sr含量增加,晶界上不连续析出的β-Mg17Al12相层片间距减小,晶内连续析出的β-Mg17Al12相减少。The effects of Sr addition on the morphology of β-Mg17Al12 phase and mechanical properties ofAZ81 magnesium alloy were investigated by using optical microscopy （OM）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and electronic tensile testing machine in this study. The results indicate that the addition of 0.3% Sr to AZ81 magnesium alloy decreases the size of β-Mg17Al12 phase obviously and leads to the formation of a new phase so-called A14Sr. Furthermore, with increasing of Sr content, the morphology of β-Mg17Al12 phase changes from continuously strip-like shape to discontinuously strip-like shape or particle-like shape. The mechanical properties ofAZ81 magnesium alloy in ambient temperature reach the highest with addition of 0.6% Sr. As Sr content increasing to 0.9%, the amount of β-Mg17Al12 reduces further, A14Sr phase segregates as discontinuously strip-like shape. After T6 treatment, a large amount of β-Mg17Al12 phases precipitate as lamellar-like shape, needle-like shape and point-like shape on grain boundaries and within grains. Simultaneously, the mechanical properties are dramatically improved. With increasing Sr content, the lamellar space between β-Mg17Al12 phases on grain boundaries and the amount of β-Mg17Al12 phase in grain interior all decrease.

关 键 词：AZ81 锶 β-Mg17Al12相 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]