Al和Ca对变形镁合金性能的影响

Effect of Al, Ca alloying elements on mechanical behavior of wrought magnesium alloys

采用环境扫描电镜(ESEM)和能谱分析研究了添加元素Al和Ca对变形镁合金结构和性能的影响.结果表明,Al是镁合金中强化相β相的组成元素,β相呈片层状,片层与镁基体α相的基面平行或垂直.Al含量的增加使镁合金中β相也增加,提高了镁合金的强度但降低了其塑性;Ca主要分布于β相中,与Mg结合生成Mg2Ca相,提高了β相的高温稳定性,改变了挤压后β相的形貌和分布,减少了再结晶过程中晶界β相的析出量,有效地提高了镁合金的塑性,但是使强度稍有降低.

The microstructure and mechanical properties of extruded Mg alloys containing AI and Ca were studied by environment scanning electronic microscope （ESEM） and TEM. Precipitated β-Mgl7Al12 phase has a lamellae structure parallel or perpendicular to the basal plane of the matrix. With increasing the content of AI, the amount of β phase increases, which leads to enhancement in yield and ultimate strengths and decrease in elongation of the alloys. The stability of β-phase at elevated temperature is enhanced by Ca due to formation of Mg2Ca phase in β phase, and results in variation of the morphology and distribution of β-phase after extrusion and decrease in the amount of the β phase at grain boundary. The plasticity of the alloys increases while strength decreases with addition of Ca.