成分和冷却速度对Al-xEr合金凝固组织的影响

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Al₃Er相为L1₂结构,尺寸约为200 μm,相与相之间以鱼骨状连接。当Er含量增大到30%时,初生Al₃Er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Al₃Er相由轮廓平直的L1₂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。

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

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 Al₃Er phase in the Al-10Er alloy is L1₂ with size of about 200 μm, which are connected in a fishbone shape. With the increase of Er content to 30%, the primary Al₃Er phase transforms into a block with size of about 1 mm. For the Al-30Er alloy, as the cooling rate decreases, the primary Al₃Er phase changes from a straight L1₂ structure to a wavy hR20 structure, and the eutectic structure changes from flocculent to striped.