复合添加Sc、Zr、Ti对Al-Mg合金组织与性能的影响

采用布氏硬度计、金相显微镜、扫描电镜(SEM)和透射电镜(TEM)研究了微量Sc、Zr、Ti以及Mg含量对Al-Mg合金的显微组织与布氏硬度的影响。结果表明,单独添加Sc、Zr元素的合金与未添加的Al-Mg合金的铸态组织相比,合金的晶粒组织得到了一定的细化,复合添加Sc、Zr、Ti3种元素的合金铸态组织的晶粒细化程度更为明显。同时在Sc、Zr、Ti相同含量下,Mg元素的增加也能进一步细化合金的晶粒组织,这是由于Mg元素固溶强化的结果,使得合金的布氏硬度提高。对Al-10Mg-Sc-Zr-Ti合金进行均匀化退火处理后,合金的硬度较铸态组织提高了10%,这是Al3(Sc1-xZrx)、Al3(Sc1-xTix)及Al3(Sc1-x-yZrxTiy)大量沉淀相二次析出,弥散度增大、分布更加均匀的结果。

Effect of Minor Sc, Zr and Ti Co-Addition on Microstructure and Properties of Al-Mg Alloys

Effect of minor Sc, Zr and Ti co-addition and Mg content on the microstructure and Brinell hardness of Al-Mg alloys was investigated by means of Brinell hardness tester, optical microscope, SEM and TEM. Results show that the grain size of the as-cast alloys was refined by the addition of Sc and Zr, and it can be further refined by the addition of Ti. With the same Sc, Zr and Ti content, the increase of Mg content is beneficial to the refinement of microstructure, which is due to the solid solution strengthening of Mg in α-Al. The refined microstructures of the as-cast alloys were favorable for the improvement of the Brinell hardness. After homogenization annealing treatment of Al-10Mg-Sc-Zr-Ti, the Brinell hardness of alloys increased by 10% owing to second precipitations of Al_3(Sc_(1-x)Zr_x), Al3(Sc_(1-x)Ti_x) and Al3(Sc1-x-yZrxTiy), increased dispersity and more homogeneous distribution.