Zr与Er复合添加后的高镁铝合金耐磨性能研究

Wear Resistance of High Mg-Al Alloy with Combining Additions of Zr and Er

Al-Mg系(5系)铝合金具有良好的加工性、耐腐蚀性和焊接性等,但中等硬度限制了其耐磨性的发挥。本研究在5系铝合金的主要元素Al-xMg-0.5Mn的基础上复合添加质量分数为0.14%Zr和0.35%Er,研究稀土高镁铝合金中(Mg含量最高达9.28%)Mg含量对其显微组织及摩擦磨损性能的影响。随着Mg含量从2.96%增加到9.28%,Al-xMg-0.5Mn-0.14Zr-0.35Er合金中形成的(Al,Mg,Mn,Er,Zr)复合白色相不断增多,尺寸不断增大,由棒条状变成细小鱼骨状,最后形成粗大鱼骨状。随着Mg含量从2.96%增加到9.28%,Er、Mg元素经常“相伴偏聚”,主要以Al(ErxMg1-x)和Al(Erx(Mg,Mn)1-x)相形式存在,由块状复合相转变成均匀分布的(Al,Mg,Mn,Er)复合相,具有一定强化作用,可显著改善合金摩擦磨损性能。复合添加0.14%Zr和0.35%Er后,合金的磨损方式从粘着磨损及磨粒磨损的混合磨损(Mg含量在2.96%~5.15%)转变到磨粒磨损为主(Mg含量在5.7%~9.28%)。随着Mg含量从2.96%增加到6.8%,合金的耐磨性逐渐提高;当Mg含量增加到8.0%~9.28%时合金耐磨性趋于稳定,400s以后瞬时摩擦磨损系数μ达到1.11~1.15稳定值。

Al-Mg alloys(5xxx aluminum alloys) have good processability, corrosion resistance and weldability, but their medium-hardness limits their wear resistance. Based on the main alloy elements of 5xxx aluminum alloys, 0.14wt% Zr and 0.35wt% Er were added into Al-xMg-0.5Mn. The effects of different contents of Mg(Mg content up to 9.28wt%) on the microstructure and friction and wear properties of high Mg aluminum alloy were studied. With the increase of Mg content from 2.96wt% to 9.28wt%, the content of(Al, Mg, Mn, Er, Zr)composite phases formed in Al-xMg-0.5Mn-0.14Zr-0.35Er alloy increases gradually, and the size also increases gradually. Their morphology changes from rod shape to fine fishbone shape, and finally forms uniformly coarse fishbone shape. When Mg content increases from 2.96wt% to 9.28wt%, Er and Mg are often “concomitant segregation”, mainly in the form of Al(ErxMg1-x) and Al(Erx(Mg, Mn)1-x).These composite phases change from massive to uniformly distributed(Al, Mg, Mn, Er) phases, which have a certain strengthening effect and can significantly improve the friction and wear performance of the alloy. After compound addition of 0.14wt%Zr and 0.35wt%Er, the wear mode of the alloy changes from the mixed wear(adhesive wear and abrasive wear: Mg content is 2.96wt%-5.15wt%) to abrasive wear(Mg content is 5.7wt%-9.28wt%). With the increase of Mg content from 2.96wt% to 6.8wt%, the wear resistance of the alloy increases gradually. When the Mg content increases to 8.0wt%-9.28wt%, the wear resistance of the alloy tends to be stable, and the instantaneous friction and wear coefficient μ reaches the stable value of 1.11-1.15.