本文研究了Zn和Cu元素的添加对纯 Mg微观组织和导电性能的影响.结果表明,Zn和 Cu 能明显细化纯Mg的铸态组织,且元素添加量越多,晶粒尺寸越细小.铸态 Mg-Zn和 Mg-Cu 合金的导电率均随着元素添加量的增加而不断降低.Mg-Zn合金中,固溶在基体中的溶质原子是影响导电率的主要因素;Mg-Cu 合金中,第二相是影响导电率的主要因素.当元素添加量相同时,Zn 对导电率的降低作用比 Cu 要更加显著.分别选取Mg-2.5%Zn合金和 Mg-4%Cu 合金在不同挤压温度下(200℃、300℃、400℃)进行挤压变形.Mg-2.5%Zn合金随着挤压温度提高,晶粒尺寸增大,第二相数量减少,导电率先降低再升高,但均低于其铸态合金的导电率.Mg-4%Cu合金随着挤压温度提高,晶粒尺寸增大,第二相数量无明显变化,导电率不断升高,均高于其铸态合金的导电率.
The effects of Zn and Cu on the microstructure and electrical conductivity of pure magnesium
In this paper,the effects of the addition of Zn and Cu on the microstructure and conductivity of pure Mg were studied.The results show that Zn and Cu can significantly refine the as-cast structure of pure Mg,and the more elements are added,the finer the grain size.The conductivity of as-cast Mg-Zn and Mg-Cu alloys decreases with the increase of element addition.In Mg-Zn alloys,solute atoms dissolved in the matrix are the main factors affecting the conductivity.In Mg-Cu alloys,the second phase is the main factor affecting the conductivity.When the amount of elements added is the same,the reduction of conductivity of Zn is more significant than that of Cu.Mg-2.5%Zn alloy and Mg-4%Cu alloy were selected for extrusion deformation at different extrusion temperatures(200℃,300℃,400℃),respectively.With the increase of extrusion temperature,the grain size of Mg-2.5%Zn alloy increases,the number of second phases decreases,and the conductivity first decreases and then increases,but it is lower than the conductivity of the as-cast alloy.With the increase of extrusion temperature,the grain size of Mg-4%Cu alloy increased,the number of second phases did not change significantly,and the conduc-tivity continued to increase,which was higher than that of the as-cast alloy.
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