时效处理对Al-Zr-Sc(-Er)合金组织和性能的影响

Effect of aging treatment on microstructureand properties of Al-Zr-Sc(-Er)alloys

通过透射电镜(TEM)和扫描透射电镜(STEM)以及硬度、电导率测试等方法系统研究了时效处理对Al-Zr-Sc三元合金以及Al-Zr-Sc-Er四元合金显微组织和性能的影响。结果表明:对于Al-Zr-Sc合金,增加Sc含量,可显著提高合金时效响应速率、峰值硬度和热稳定性;增加Zr含量,显著提高了合金硬度和热稳定性,但会降低电导率。在Al-Zr-Sc合金中添加Er,进一步提高了合金的时效响应速率,促进了Zr,Sc的脱溶析出。Er与Zr,Sc形成具有核-双壳结构的Al 3(Er,Sc,Zr)相,明显改善合金的硬度和电导率。经300℃单级时效,实验合金硬度较高,但电导率相对较低;经400℃单级时效,实验合金时效响应速率加快,电导率明显提高,但硬度显著下降;经300℃/24 h+400℃的双级时效实验合金可获得电导率、强度和热稳定性的良好匹配。

The effects of aging treatment on microstructure and properties of Al-Zr-Sc(-Er)alloys were investigated by TEM,STEM,hardness tests and electric conductivity tests systematically.Results show that the aging response speed,peak hardness and thermal stability of Al-Zr-Sc alloys are significantly improved by increasing Sc content,and increasing Zr content improves hardness and thermal stability,while decreasing the electric conductivity.Adding Er in Al-Zr-Sc alloys improves the aging response speed and promotes the precipitation of Zr and Sc.Hardness and electrical conductivity of alloy are improved,owing to the formation of Al 3(Er,Sc,Zr)phases with core-double shell structure.For experimental alloys,one-stage aging at 300℃provides the higher hardness but lower electric conductivity;one-stage aging at 400℃can increase the aging response speed and electrical conductivity but decrease hardness;two-stage aging at 300℃/24 h+400℃can lead to better match of conductivity,tensile strength and heat resistance.