摘要
基于密度泛函理论,研究了合金元素Zr、Hf、Nb、Ta对NiAl合金的电子结构、力学性能和热学性能的影响,分析了合金相的晶胞参数、态密度、韧脆性以及焓、自由能、熵、德拜温度和热容。研究表明:Zr、Hf、Nb和Ta在晶胞结构中都倾向于取代Al位点,合金化后晶胞的晶格参数和晶胞体积均增加到不同程度。态密度图显示0~20 eV能量范围内,态密度分布均较为平均,没有局域的态密度(density of states,DOS)尖峰,-10~0 eV能量区间内态密度均出现最强峰。由柯西压力值判断,Zr、Hf、Nb、Ta的加入均使柯西压力值增大,且合金相模量比(ratio of shear modulus to bulk modulus,G/B)的值均小于0.57,合金相表现出相对韧性。在0~1700 K温度范围内,合金相的焓、熵均随温度的升高而增大,当温度高于400 K时,合金相的德拜温度均趋于420 K;随着温度的升高,合金相的热容值均趋近于杜隆-珀蒂极限值,表明合金化后结构体现出良好的热力学性能。
The effects of alloying element Zr,Hf,Nb and Ta on the electronic structure,mechanical properties and thermal properties of NiAl alloys were studied by density functional theory(DFT),and the cell parameters,density of states,toughness and brittleness,enthalpy,free energy,entropy,Debye temperature and heat capacity of the alloy phase were analyzed.The results show that Zr,Hf,Nb and Ta tend to replace the Al sites in the cell structure,the lattice parameters of the cell and the cell volume increase to different degrees after alloying.The density of states shows that the density of states distribution is average,and there is no local density of states(DOS)peak in the energy range of 0~20 eV,the peak of density of states appeared in the energy range of-10~0 eV.According to the Cauchy pressure values,the addition of Zr,Hf,Nb and Ta increases the Cauchy pressure,and the ratio of shear modulus to bulk modulus(G/B)values of the alloy phase are less than 0.57,and the alloy phase shows relative toughness.In the temperature range of 0~1700 K,the enthalpy and entropy of the alloy phase increase with the increase of temperature.When the temperature is 400 K,the Debye temperature of alloy phase tends to 420 K.With the increase of temperature,the heat capacity values of the alloy phase tend to the Dulon-Petit limit value,which shows that the structure of alloy shows good thermodynamic properties.
作者
卢彩彬
李新梅
LU Cai-bin;LI Xin-mei(College of Mechanical Engineering, Xinjiang University, Urumqi 830047, China)
出处
《科学技术与工程》
北大核心
2021年第25期10646-10653,共8页
Science Technology and Engineering
基金
国家自然科学基金(51865055)
新疆自治区天山英才计划(201720025)。
关键词
NIAL合金
第一性原理
电子结构
力学性能
热学性能
NiAl alloy
first-principles
electronic structure
mechanical properties
the thermal performance
