稀土元素Sm的添加含量对AZ61镁合金的组织与力学性能的影响

Effect of trace Sm addition on microstructure and mechanical properties of AZ61 magnesium alloys

摘要:

采用OM, XRD, SEM和EDS等分析手段，研究了不同含量的稀土元素钐(0, 0.5, 1, 1.5 和2 wt.%)对AZ61镁合金组织与性能的影响。结果表明：在含钐为0.5-2.0wt.%的AZ61镁合金中发现了大量的颗粒状Al2Sm金属间化合物（体积含量为0.4-2.2 vol.%），这些颗粒的直径约为1-7μm。当合金中稀土元素钐的含量从0%增加到2%时，合金中Al2Sm颗粒尺寸逐渐长大，而β-Mg17Al12的含量却不断减小。同时经693K固溶24h的含钐AZ61镁合金的晶粒随着钐含量的增加而减小，但钐含量超过1%时，合金的晶粒尺寸呈现逐渐长大的趋势。本实验条件下，固溶态AZ61镁合金中的钐含量达到1%时，合金的极限抗拉强度、屈服强度和延伸率都到达最大，分别为215 MPa、142 MPa和4.1%。

Abstract:

The effect of samarium (Sm) adding (0, 0.5, 1, 1.5 and 2 wt.%) on the microstructure and mechanical properties of AZ61 magnesium alloy was investigated by OM, XRD, SEM and EDS. The results indicated that 0.4-2.2 vol.% Al2Sm particles with the average diameter of 1-7μm were found in AZ61 magnesium alloy with different Sm content addition. When rare earth element Sm content increased from 0 to 2.0 wt.%, the size of Al2Sm particles gradually increased and the content of β-Mg17Al12 was decreased. Meanwhile the grain size of AZ61-xSm magnesium alloy with solution treatment at 693K for 24h firstly decreased with Sm content increased to 1.0 wt.%, then gradually increased when Sm content excessed 1.0 wt.%. The maximum values of the ultimate tensile strength and the yield strength of AZ61-xSm magnesium alloys with solution treatment were 215 and 142 MPa, respectively, for the alloy with 1.0 wt.% Sm. And the maximum elongation (4.1%) of AZ61-xSm magnesium alloys was also achieved with 1.0 wt.% Sm addition.