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Mechanical properties of defective L12-Al3X (X = Sc, Lu) phase: A first-principle study
Journal of Rare Earths ( IF 4.9 ) Pub Date : 2021-02-01 , DOI: 10.1016/j.jre.2020.04.006
Yu Wang , Yanan Meng , Junsheng Wang , Chi Zhang , Houbing Huang

Abstract The mechanical properties of Al3X (X = Sc, Lu) were studied by density functional theory (DFT). The elastic constants and formation enthalpy indicate that the L12 Al3X (X = Sc and Lu) are mechanically and thermodynamically stable. The bulk moduli and shear moduli show that Al3Sc has better resistance to volume and shape changes than Al3Lu. However, the calculated results show that Al3Lu has better plasticity than Al3Sc. The properties of structural stability and elastic moduli of the crystal containing four major types of point defects in L12-A13X (X = Sc and Lu) were calculated. The mechanical properties of point defects show that point defects cause L12-Al3X lattice distortion and change the corresponding elastic constants. Point defects reduce the Young's, shear and bulk moduli but have little effects on the crystal brittleness and toughness of Al3Sc and Al3Lu. Therefore, we have found that Lu addition into aluminum alloys is a very good replacement for expensive Sc addition when the L12 structures are desired for nucleation or strengthening precipitates in aluminum alloys.

中文翻译:

缺陷 L12-Al3X (X = Sc, Lu) 相的机械性能:第一性原理研究

摘要 采用密度泛函理论(DFT)研究了Al3X(X = Sc, Lu)的力学性能。弹性常数和形成焓表明 L12 Al3X(X = Sc 和 Lu)在机械和热力学上是稳定的。体积模量和剪切模量表明,Al3Sc 比 Al3Lu 具有更好的抗体积和形状变化能力。然而,计算结果表明Al3Lu 比Al3Sc 具有更好的塑性。计算了L12-A13X(X = Sc和Lu)中含有四种主要类型点缺陷的晶体的结构稳定性和弹性模量的性质。点缺陷的力学性能表明,点缺陷引起L12-Al3X晶格畸变并改变相应的弹性常数。点缺陷减少杨氏,剪切和体积模量,但对 Al3Sc 和 Al3Lu 的晶体脆性和韧性影响不大。因此,我们发现,当需要 L12 结构用于成核或强化铝合金中的析出物时,向铝合金中添加 Lu 是一种非常好的替代昂贵的 Sc 添加。
更新日期:2021-02-01
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