【作者】 徐航；

【导师】 周宏； 刘海峰；

【作者基本信息】 吉林大学 ， 材料工程， 2012， 硕士

【摘要】 论文进行了添加稀土氧化镧原矿制备含镧AZ31变形镁合金的研究。采用添加氧化镧原矿的方法制备了镧含量在0-2.0wt.%之间的AZ31变形镁合金,并与采用Mg-La中间合金制得的合金就组织和性能进行了对比。研究发现,添加氧化镧原矿同样可以制得含镧AZ31变形镁合金,并且在相同的镧含量下,其组织和性能与采用Mg-La中间合金制得的合金相近。在熔炼时,将La2O3原矿粉末与精炼剂混合后加入到镁溶液中,一边添加一边搅拌,不但能保护熔体、精炼除渣,还能使La2O3与镁溶液的反应更加彻底。通过正交试验,发现搅拌时间对La回收率的影响最为显著,La2O3的添加量次之,熔炼温度影响最小。确定了获得高La回收率的最优方案：La2O3添加量80g、搅拌时间60min、熔炼温度710℃添加La203原矿粉末制备的AZ31-La合金在La含量相同时,其晶粒尺寸与添加Mg-La中间合金制得合金的尺寸相近,在La含量为0.95wt.%时,合金的晶粒尺寸达到最细小的10.3μm。添加La2O3原矿粉末制得的AZ31-xLa合金的拉伸性能与相同La含量下添加Mg-La中间合金制得合金的拉伸性能相近,当La含量为0.94wt.%时,合金的抗拉强度最高,为216MPa,相比不含La的AZ31合金提高了56%。添加La2O3原矿粉末制得合金的单道次最大轧制率和多道次最大总轧制率与添加Mg-La中间合金制得的合金相近,当La含量为0.95wt.%时,合金的轧制性能最佳,合金的单道次最大轧制率为41.1%,多道次最大总轧制率为81.9%。添加La2O3原矿粉末制得的AZ31-xLa变形镁合金镁屑的起燃点与采用Mg-La中间合金制备合金的燃点相近,在La含量为0.61wt.%时达到最高的571.8℃。同时,450℃下合金的氧化膜与添加Mg-La中间合金制备的AZ31-xLa合金的氧化膜一样致密,抗氧化性能相近。通过添加La2O3原矿粉末的方法完全可以代替添加Mg-La中间合金制得性能良好的AZ31-xLa变形镁合金,并且省略了中间合金的制备过程,节约了成本,为稀土变形镁合金的开发提供了新的道路,对工业生产有重要的经济意义。更多还原

【Abstract】 This article conducted a study of adding rare earth La2O3to prepare wroughtmagnesium alloy containing La. By using the method of adding lanthanum oxide,AZ31wrought alloy containing La content between02.0wt.%was prepared. And themicrostructures and properties was compared with the alloy which prepared byMg La intermediate alloy. This study shows that AZ31wrought alloy containing Lacan be prepared by adding lanthanum oxide. In the same La content, itsmicrostructures and properties is similar to the alloy prepared by Mg La intermediatealloy.In the smelting process, lanthanum oxide was mixed with refining agent. Thenadd them into the magnesium solution, stirring while adding. It can not only protectthe melt, remove the slag, but also make the reaction between La2O3and magnesiumsolution thoroughly. According to the orthogonal experiment, it is found that theinfluence of mixing time on the recover rate of La is the most significant, followed theadditive amount of La2O3, melting temperature the least.The optimal solution wasdetermined: additive amount of80g, mixing time of60min, melting temperature of7102). For the alloy prepared by La2O3in the same La content, its grain size is similarto the one prepared by Mg La intermediate alloy. In the La content of0.95wt.%, theminimum grain size of alloy is10.3μm. The tensile strength of the alloy prepared byLa2O3is similar to the one which prepared by Mg La intermediate alloy. In the Lacontent of0.95wt.%, the maximum tensile strength is216MPa, increased by56%.The maximum reduction per rolling pass and maximum total reduction of the alloyprepared by La2O3is similar to the one which prepared by Mg La intermediate alloy.In the La content of0.95wt.%, alloy has the best rolling performance. The maximumreduction per rolling pass is41.1%, the maximum total reduction is81.9%.The ignition point of alloy is similar to the alloy prepared by Mg La intermediate alloy. In the La content of0.61wt.%, the maximum ignition point is571.82). At thesame time, under the temperature of4502), the oxide film is as compact as the alloyprepared by Mg La intermediate alloy. The antioxidant performance of these twoalloy is similar.By using La2O3powder, instead of Mg La intermediate alloy, high performancewrought alloy containing La can be prepared. This method not only omits thepreparation of Mg La intermediate alloy, but also save the cost. A new path for thedevelopment of rare earth wrought magnesium alloy was provided, it has animportant economic significance for industrial production.更多还原