成分和冷却速度对Al-xEr合金凝固组织的影响

Effects of composition and cooling rate on solidification structure of Al-xEr alloy

用扫描电镜(SEM)和X射线衍射仪(XRD)分析了Al-xEr(x=10、20、30,质量分数,%)合金凝固组织的形貌和相结构。结果表明,在60℃/h的冷却速率下,Al-10Er合金中Al_(3)Er相为L1_(2)结构,尺寸约为200μm,相与相之间以鱼骨状连接。当Er含量增大到30%时,初生Al_(3)Er相呈块状,尺寸约为1 mm。对Al-30Er合金,随冷却速率的降低,初生Al_(3)Er相由轮廓平直的L1_(2)结构转变为轮廓呈波浪状的hR20结构,同时共晶组织由絮状转变成条状。

Microstructure and phase structure of solidified structure of the Al-xEr(x=10,20,30,mass fraction,%)alloy were analyzed by means of scanning electron microscope(SEM)and X-ray diffractometer(XRD),respectively.The results show that at cooling rate of 60℃/h,the structure of Al_(3)Er phase in the Al-10 Er alloy is L1_(2) with size of about 200μm,which are connected in a fishbone shape.With the increase of Er content to 30%,the primary Al_(3)Er phase transforms into a block with size of about 1 mm.For the Al-30 Er alloy,as the cooling rate decreases,the primary Al_(3)Er phase changes from a straight L1_(2) structure to a wavy hR20 structure,and the eutectic structure changes from flocculent to striped.