用SEM、XRD和EDS分析了添加0.5%,1.0%,1.5%铈、镧和富铈稀土的AZ91D合金的微观组织形貌和相组成:并测试了各合金的硬度以及不同温度下的拉伸性能.结果表明：铈、镧和富铈稀土的添加均能细化AZ91D合金α相,降低β相含量,同时形成针杆状Al11RE3化合物.添加同一稀土元素的合金中,当稀土含量为1.0%时,其常温和高温抗拉强度达到最大值.对比相同含量不同元素的作用,低含量时含铈合金抗拉强度较好,高含量时含镧合金常温和高温断后伸长率较高:铈、富铈混合稀土、镧提高合金硬度的作用依次减弱.

Effects of adding 0.5%,1.0%,1.5%Ce,La and Ce-rich MM to AZ91D alloy were studied.The microstructure and components of these alloys were investigated by scanning electron microscopy (SEM),energy dispersion spectrum (EDS) and X-ray diffraction (XRD).The hardness and tensile mechanical properties of room temperature and elevated temperature were also tested.The results indicates that either of Ce,La and Ce-rich MM can reduce the α-phase grain size,reduce the β-phase content and form needle-like Al11RE3 phase.When addition content is 1.0%,the room temperature and elevated temperature tensile strength of alloy arrived at maximum.Compare the alloys with different element but the same addition amount:the tensile strength of alloy with Ce is higher in low addition amounts condition;the elongation of alloy with La is greater in high addition amounts condition;the rigidity of Ce addition alloy is the highest,the rigidity of La addition alloy is the lowest.