【摘要】 借助SEM、EDS、XRD、DTA等研究了Al4C3和Ce加入对AZ91D镁合金铸态组织和性能的影响。结果表明:加入0.6%Al4C3能显著细化合金晶粒,使粗大骨骼状β相和层片状α+β共晶组织转变为蜂窝状的部分离异共晶组织,同时β相的尺寸变小、分布较均匀。在此基础上,复合添加0.2%Ce后细化效果更好,β相分布更趋均匀且含量减少。此外,组织中有少量针状化合物Al4Ce形成。通过错配度计算、能谱分析以及差热分析,证实了Al4C3可成为初生α-Mg的良好异质核心。显微组织的细化有利于合金强度性能及耐腐蚀性能的明显提高。更多还原

【Abstract】 The microstructure and performances of AZ91D alloy with Al4C3 and Ce were investigated by using of SEM, XRD, EDS and DTA. It was found that 0. 6% Al4C3 addition to AZ91D magnesium alloy leads to the α-Mg grain size obvious decreasing, the bulk skeletal fully-divorced eutectic β-phases and lamellar α+β eutectic structure transforming into honeycomb-like partially-divorced eutectic β-phases, and the β-phases diminishing in size and uniform distribution. Combining addition of 0. 6%Al4C3 and 0. 2%Ce to AZ91D magnesium alloy resulted in better grain refining effect, the β-phases breaking, reducing in amount and distributing more uniformly, furthermore a small amount needle-like compound Al4Ce were found. Based on the analysis resulting of EDS, DTA and calculation of the disregistry between Al4C3 and Mg, Al4C3 particles can act as the heterogeneous nuclei. Microstructure refinement of AZ91D alloy is favorable for significant improvement of strength, hardness and corrosion resistance. It is also benefit for enhancement of elongation percentage.更多还原