钇对2519铝合金铸态组织的影响

Effect of yttrium on as-cast microstructure of 2519 aluminum alloy

采用X射线、光学显微镜及扫描电镜等研究质量分数为0～0.3%的钇对2519铝合金铸态组织的影响.研究结果表明:添加0.1%的钇后2519铝合金的铸态组织明显细化,铸态晶粒尺寸由100μm减少到70μm;但当钇含量超过0.1%时,合金的铸态组织随着钇含量的增加又逐渐粗化;当钇含量为0.3%时,合金铸态晶粒尺寸达200μm左右;钇加入2519铝合金中主要形成Al6Cu6Y稀土化合物并沿晶界分布;钇改变了合金铸态中第二相的形貌及大小,加入适量的钇(0.1%)对2519铝合金铸态中的第二相具有球化和细化作用.

The effects of yttrium （0-0.3%,mass fraction） on as cast microstructure of 2519 aluminum alloys were investigated by means of X-ray diffraction, optical microscope and scanning electron microscope. The experimental results show that the as-cast microstructure of 2519 aluminum alloy is fined and the grain size is reduced from 100μm to 70μm with addition of 0. 1%yttrium. When more than 0.1% yttrium is added to 2519 aluminum alloy, the as-cast microstructure of the alloy is coarsed gradually with the increase of the yttrium content. The grain size of the as-cast alloy is about 200μm with the addition of 0.3% yttrium. The Al6Cu6Y phase is formed at the grain boundary of as-cast and the second phase is granulated, sphercized and fined with the addition of yttrium.