La-Ce混合稀土对Mg-Al-Mn合金力学性能及耐蚀性能的影响

研究了La-Ce混合稀土对Mg-Al-Mn合金组织形貌、力学性能及耐蚀性的影响。采用T-1200CB坩埚炉冶炼稀土含量(质量分数)分别为4.63%、5.81%、6.18%的Mg-Al-Mn合金。在箱式电阻炉中对研究试样进行430 ℃保温24 h的固溶处理,然后进行200 ℃保温24 h时效处理。对不同热处理状态的试样进行组织观察,对固溶时效后的试样进行拉伸、硬度及盐雾腐蚀试验,从而分析La-Ce混合稀土对Mg-Al-Mn合金显微组织、力学性能及耐蚀性的影响。研究表明,随着合金中的La-Ce混合稀土含量的增加,Mg₁₇Al₁₂相逐渐被Al₄(La, Ce)相代替;硬度、抗拉强度和伸长率都逐渐减小,力学性能下降;合金的腐蚀速率逐渐下降,耐蚀性提高。

Effect of La-Ce mixed rare earth on mechanical properties and corrosion resistance of Mg-Al-Mn alloy

Effect of La-Ce mixed rare earths on the microstructure, mechanical properties and corrosion resistance of Mg-Al-Mn alloys were investigated. The Mg-Al-Mn alloys with rare earth content (mass fraction) of 4.63%, 5.81% and 6.18% respectively were smelted in a T-1200CB crucible furnace. The specimens were solution treated at 430 ℃ for 24 h in a box-type resistance furnace, and then aged at 200 ℃ for 24 h. The microstructure of the specimens in different heat treatment states were observed, the tensile, hardness and salt spray corrosion tests were carried out on the specimens after solution treatment and aging. The effects of mixed rare earth on the microstructure, mechanical properties and corrosion resistance of the alloys were analyzed. The results show that with the increase of La-Ce mixed rare earth content in the alloy, the Mg₁₇Al₁₂ phase is gradually replaced by the Al₄(La, Ce) phase; the hardness, tensile strength and elongation are gradually reduced, and the mechanical properties are decreased; the corrosion rate of the alloy is gradually decreased and the corrosion resistance is improved.