铝合金夹杂物基本性质的第一性原理研究

A first principle study on the basic properties of inclusions in aluminum alloy

  • 摘要: 采用第一性原理计算的方法研究了铝合金基体及常见夹杂物Al2O3、MgO、AlN、TiB2、AlB2、Al4C3的基本性质.形成热的计算结果表明Al2O3最容易形成,其次是MgO,AlB2相对最难形成;Al2O3、AlN、TiB2结合能的绝对值稍微大于其他物相,且TiB2最稳定,AlB2相对最不稳定;TiB2粒子的切变模量、体模量、杨氏模量和硬度均最高,Al4C3与基体硬度最接近,表明TiB2粒子对铝合金强度、刚度、加工性能的影响最大;AlN粒子的各向异性因子最大,其对铝合金各向异性的影响最大,AlB2次之,Al2O3和TiB2粒子对铝合金各向异性程度影响较小;TiB2对铝合金韧性的影响最大,AlN次之,Al4C3对铝合金韧性的影响最小;Al2O3与铝基体之间的相对费米能级差较大,为1.4 eV,而AlB2粒子最小,各夹杂物对材料腐蚀性能的影响大小顺序为:Al2O3>MgO>TiB2>Al4C3>AlN>AlB2.

     

    Abstract: The basic properties of aluminum alloy matrix and common inclusions of Al2O3, MgO, AlN, TiB2, AlB2, Al4C3 in aluminum alloy were studied by means of first principles calculation. The formation heat reveals that Al2O3 is the easiest to form, while MgO and AlB2 are the most difficult to form. The absolute value of binding energy of Al2O3, AlN and TiB2 are slightly larger than others, which suggests that TiB2 is the most stable particle while AlB2 is the most unstable one. TiB2 holds the highest shear modulus, bulk modulus, Young's modulus and hardness. The hardness of Al4C3 is the closest one to aluminum alloy matrix, which indicates that TiB2 has the largest impact on the strength, stiffness and processing performance of aluminum alloy. The anisotropy factor of AlN particles is the largest, and its influence on that of aluminum alloy is also the largest, then followed by AlB2. The influence of Al2O3 and TiB2 particles on the anisotropy of aluminum alloy is small. The impact of TiB2 on the toughness of aluminum alloy is the greatest, followed by AlN, and Al4C3 is the smallest. The relative Fermi difference between Al2O3 and aluminum matrix is the largest, i.e. 1.4eV. AlB2 particle is the smallest. The influence of the studied inclusions on corrosion properties of materials is in the order of Al2O3>MgO>TiB2>Al4C3>AlN>AlB2.

     

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