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采用普通铸造法制备了Mg-3Al-x Sr(x=0.1~0.9,质量分数,%)系列合金。利用金相显微镜、XRD、SEM、电导率测量仪和显微硬度仪等手段对该系列合金的金相组织、显微结构、电导率及维氏显微硬度等性能进行了测试。结果表明,在Mg-3Al合金中添加少量Sr元素(<0.1%)会生成Al4Sr相,而继续增加Sr后(>0.1%)合金中开始出现Mg-Al-Sr相(τ相),Mg-Al-Sr铸态合金的电导率因此随着Sr含量的增加而不断提高;经高温热处理后(400℃),热处理态Mg-Al-Sr合金的电导率均随着热处理时间的延长而不断增加,这主要是由τ相逐渐分解并转变为Al4Sr相引起的;添加少量的Sr(<0.1%)会降低Mg-3Al合金的显微硬度,而随着Sr元素的继续添加(>0.1%),合金的显微硬度先增大后减小,并在Sr含量达到0.6%时达到峰值;此外,高温热处理会降低Mg-Al-Sr铸态合金的显微硬度。
The Mg-3Al-x Sr (x = 0.1-0.9, mass fraction,%) series alloys were prepared by the common casting method. The microstructure, microstructure, electrical conductivity and Vickers microhardness of this series of alloys were tested by metallographic microscope, XRD, SEM, conductivity meter and microhardness tester. The results show that the addition of a small amount of Sr (<0.1%) to the Mg-3Al alloy results in the formation of the Al4Sr phase, whereas the Mg-Al-Sr phase (τphase) The electrical conductivity of Al-Sr cast alloy increases with the increase of Sr content. The electrical conductivity of Mg-Al-Sr alloy after heat treatment at 400 ℃ increases with the increase of heat treatment time , Which is mainly caused by the gradual decomposition of τ phase into Al4Sr phase. Adding a small amount of Sr (<0.1%) will reduce the microhardness of Mg-3Al alloy. With the continuous addition of Sr (> 0.1%), , The microhardness of the alloy first increases and then decreases, and reaches the peak value when the content of Sr reaches 0.6%. In addition, the high temperature heat treatment will reduce the microhardness of Mg-Al-Sr cast alloy.