稀土Ce和Y對(duì)AZ80鎂合金組織和力學(xué)性能的影響Effects of rare-earth Ce and Y on microstructure and mechanical properties of AZ80 Mg alloys

通過(guò)元素分析、性能測(cè)試、XRD、SEM和TEM等手段分析了稀土Ce和Y對(duì)AZ80鎂合金熔煉、組織和力學(xué)性能的影響規(guī)律。結(jié)果表明：在AZ80合金熔煉過(guò)程中，添加稀土Y元素能夠起到有效除Fe的作用； AZ80合金中分別添加1%(質(zhì)量分?jǐn)?shù))的Ce和Y，可以顯著細(xì)化合金的晶界第二相，并在晶界上分別生成針狀的Al₁₁Ce₃相和塊狀的Al₂Y相；擠壓變形后，Al-RE相在晶界上能夠通過(guò)阻止位錯(cuò)運(yùn)動(dòng)而有效抑制再結(jié)晶晶粒長(zhǎng)大；擠壓+ T5處理后，含1%Y的合金具有最好的力學(xué)性能，抗拉強(qiáng)度和屈服強(qiáng)度分別達(dá)到390和250 MPa，而含1%Ce的合金無(wú)論是在擠壓態(tài)還是T5處理后，其力學(xué)性能最低。

The effects of rare-earth Ce and Y on the melting, microstructure and mechanical properties of AZ80 Mg alloys were investigated by elementary analysis, mechanical properties examination, XRD, SEM and TEM. The experimental results show that the content of Fe decreases obviously during alloy melting, and the melting time is shortened when Y is added into AZ80. The as-cast microstructure of AZ80 alloys is refined, and needle-like Al₁₁Ce₃ and block-like Al₂(Y, Mn) phases generate at grain boundary when 1%Ce and 1%Y (mass fraction) are added into AZ80 alloys. After extrusion, the coarsening of recrystallized grain is depressed by Al-RE phases impeding motion of dislocation at grain boundary. And after extrusion+T5(177 ℃, 0-30 h) heat-treatment, the maximum tensile strength of AZ80 alloy containing 1%Y is obtained with ultimate tensile stress of 390 MPa and yield stress of 250 MPa.

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