钕对Mg-5Al-1Si高温蠕变及组织性能的影响

Effect of Neodymium on Microstructure and High Temperature Creep Properties of Mg-5Al-1Si Magnesium Alloy

研究了不同Nd含量对Mg 5Al 1Si镁合金的高温蠕变性能影响 ,对析出相进行了分析 ,研究了微观组织与力学性能的关系。研究结果表明 ,该合金中的主要强化相Mg2 Si呈粗大的汉字状 ,分布在晶界的周围 ,在受到应力时 ,这种汉字状相与基体的界面处易产生微裂纹 ,降低合金的抗拉强度、塑性等力学性能。在Mg 5Al 1Si合金中加入微量的Nd以后 ,合金的组织得到明显的细化 ,并使Mg2 Si强化相形貌由粗大的汉字状转变为细小、弥散分布的颗粒状。由于显微组织的改善 ,使得Mg 5Al 1Si镁合金的室温和高温力学性能均有一定的提高 ,并明显的改善了Mg 5Al 1Si的抗蠕变性能。

The influence of different contents of Nd on microstructure of Mg-5Al-1Si alloys was studied. Also, the precipitating phases were identified and their influence on the mechanical properties of alloy were investigated. The study shows that the main strengthening phase Mg_2Si presented as coarse Chinese script distributed around the grain boundary after addition of 1%Si to Mg-5Al alloys. Under stress the microcrack prefers to occur in the interface between the phase Mg_2Si and the matrix. Addition of small amount of Nd to Mg-5Al-1Si alloys resulted in refinement of microstructure. Morphology of the Mg_2Si phases changes from coarse Chinese script shape to fine polygonal shape. Owing to the improvement of microstructure, the mechanical properties of Mg-5Al-1Si alloys at both ambient and elevated temperatures are increased. The high temperature creep resistant properties of Mg-5Al-1Si-xNd raises with the raising of Nd content.