半固态AZ91D镁合金制备工艺的研究

Preparing Process of Semi-solid Magnesium Alloy AZ91D

研究了添加微量Sr并控制合金的浇注温度制备半固态AZ91D镁合金的工艺,考察了不同的Sr含量和浇注温度对合金凝固组织的影响及部分重熔后合金的微观组织。研究结果表明:通过添加微量的Sr并降低合金的浇注温度,可以获得非枝晶组织的半固态合金坯料;随着Sr含量的增加或浇注温度的降低,合金的晶粒尺寸逐渐减小,其初生相由枝晶向蔷薇状晶体转变;添加0.1wt%的Sr,610℃下浇注的合金经过部分重熔后,初生相为球状或颗粒状,基本具备触变过程所需要的组织状态。

The Preparing process of semi-solid magnesium alloy AZ91D was investigated by adding tiny Sr and controlling pouring temperature. The influence of different content of Sr and pouring temperature on solidification structure of the alloy was studied. The partial remelted microstructure of the alloy was analyzed. The results show that the semi-solid alloy of AZ91D with non-dendrite structure can be obtained by adding tiny Sr and controlling pouring temperature; the grain size decreases and the primary phase translates from dendrite to rosette crystal with the increases of Sr content or decrease of pouring temperature; the partial remelted microstructure of the alloy with 0. lwt% Sr addition and pouring temperature 610℃ has fine microstructure, its initial phase is spherical, it is basically suitable for thixoforming.