稀土La对含4wt.%Sn铸造铝合金阻尼性能的提高机制

The mechanism of Rare Earth La improving the damping property of cast aluminum alloy with 4wt.% Sn

摘要:

采用高阻尼铝合金对于构件或装备的轻量化和减震降噪具有重要意义。但由于Al的本征阻尼性能较低，通过合金化和引入高阻尼第二相等方法是提高铝合金阻尼性能的发展方向之一。本文研究了稀土La对含4%Sn铸造铝合金组织、阻尼和力学性能的影响，从La对Sn的形态和分布、La对Sn和铝合金基体润湿特性的影响等方面探讨了阻尼提高机制。研究结果表明， La含量为0.2%时，4%Sn的AlMgMnSi合金晶粒尺寸得到细化，β-Sn由大颗粒状变为细小、弥散分布，继续提高La含量至0.83%，晶粒变大，且在晶界处出现块状稀土化合物。La的加入可以有效提高含4%Sn铸造铝合金的阻尼性能，当La添加量为0.2%时，含4%Sn的AlMgMnSi和ZL102合金分别比不添加La的提高了约70%和100%。La改善了β-Sn与铝基体的润湿性，使β-Sn呈弥散、细小分布，从而有利于提高相界面阻尼，是本文试样具有较高阻尼性能的主要原因。

Abstract:

The use of high damping Al alloy is of great significance for lightweight components or equipment and shock absorption and noise reduction. However, due to the low intrinsic of Al alloy, it is one of the development directions to improve the damping properties of Al alloy by alloying and introducing high damping second phase. The influence of rare earth La on the microstructure, damping and mechanical properties of cast aluminum alloy containing 4 wt.%Sn is studied. The damping improvement mechanism is discussed from the aspects of La on the morphology and distribution of Sn, and the influence of La on the wetting characteristics of Sn and aluminum alloy matrix. The results show that when the La content is 0.2 wt.%, the grain size of 4 wt.%Sn AlMgMnSi alloy is improved, and the β-Sn from large granular to fine, diffuse distribution.The La content increase to 0.83 wt.%, the grain size becomes larger and the bulk rare earth compounds appear at grain boundary. The addition of La can effectively improve the damping performance of the cast aluminum alloy containing 4 wt.%Sn. When the La addition amount is 0.2 wt.%, the damping property of AlMgMnSi with 4wt.%Sn and ZL102 alloy increase by about 70% and 100%. Respectively, La improves the wettability of β-Sn and aluminum matrix, make the β-Sn diffuse and fine distribution, thus improving the phase interface damping, which is the reason for the high damping performance of the samples.