铸态及挤压态Mg-11Li-3Al-xZr合金的组织及性能  

Microstructures and Mechanical Properties of As-cast and Extruded Mg-11Li-3Al-xZr Alloy

作　　者：刘旭贺[1,2] 解海涛[2] 刘洋[2] 肖阳[2] 

机构地区：[1]河南工程学院机械工程学院 [2]郑州轻金属研究院金属材料研究所

出　　处：《特种铸造及有色合金》2017年第8期816-820,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51371161)

摘　　要：通过真空感应熔炼及挤压变形制备了铸态及挤压态的Mg-11Li-3Al-xZr(x=0、0.1)合金,采用OM、XRD、SEM、EDS观察并分析了合金的显微组织,测试了不同状态合金的力学性能。结果表明,Mg-11Li-3Al-xZr合金均含有β-Li、α-Mg、θ-MgLi_2Al、AlLi相,Mg-11Li-3Al-0.1Zr合金中还存在Al_3Zr相。铸态合金晶粒粗大,挤压变形过程中发生动态再结晶使晶粒细化。Zr的添加能明显细化晶粒,尤其在挤压后Mg-11Li-3Al-0.1Zr合金晶粒尺寸仅为Mg-11Li-3Al合金的1/4左右。铸态时两种合金力学性能相近,Mg-11Li-3Al-0.1Zr合金伸长率略低;挤压变形后两种合金伸长率较高,而且由于加工硬化和细晶强化作用,强度明显提高,Mg-11Li-3Al-0.1Zr合金的强度达到194 MPa,较铸态提高32.8%。Mg-11Li-3Al-xZr（x=0,0.1）alloys were prepared by vacuum induction melting and extrusion,and microstructure of the as-cast and as-extruded alloys was observed and analyzed by OM,XRD,SEM and EDS,meanwhile,mechanical properties of the alloys were tested by tensile testing.The results indicate that the Mg-11Li-3Al-xZr（x=0,0.1）alloys consist ofβ-Li,α-Mg,θ-MgLi2Al and AlLi phase.In addition,Al_3Zr phase exists in Mg-11Li-3Al-0.1Zr alloy.The grain size of the as-cast alloy exhibits coarse,while dynamic recrystallization occurs during the extrusion deformation.The addition of Zr can refine grain size obviously,where the grain size of Mg-11Li-3Al-0.1Zr alloy is only about 1/4of Mg-11Li-3Al alloy after extrusion.Mechanical properties of the two as-cast alloys are similar,while the elongation of Mg-11Li-3Al-0.1Zr is lower than that of the Mg-11Li-3Al alloy.After extrusion,the two alloys still have the high elongation,and the strength is increased obviously due to working hardening and fine grain strengthening effect.The strength of the Mg-11Li-3Al-0.1Zr alloy reaches 194 MPa,which is increased by 32.8% compared with that of the cast alloy.

关 键 词：镁锂合金 挤压 显微组织 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]