论文标题
TA-NB-HF-ZR高渗透合金的计算属性预测
Computational property predictions of Ta-Nb-Hf-Zr high-entropy alloys
论文作者
论文摘要
难治性的高熵合金（R-HEAS）具有高强度和高硬度材料的性质和用途，用于环境和高温，航空航天和核辐射耐受性应用，骨科应用等。在这项研究中，我们在计算上获得了tanbhfzr合金的各种特性，例如配置熵在热力学特性中的作用，纳米结构形态在热退火系统中的进化速率，基于错位模拟的基于脱位的定量定量预测，屈服强度的定量预测，脱位的性质，通过短范围（src）和质量的质量范围降级的性质。仿真始于基于混合蒙特卡洛/分子动力学（MC/MD）基于纳米结构的纳米结构演变，其沿[1 1 1]，[-1 1 1 0]，[-1 1-1 2]的主轴形成的BCC晶格结构的初始随机固体溶液合金结构适用于1/2 [1 1 1 1 1]边缘位置。热力学特性是根据下一个邻居键计数统计数据从焓变和配置熵的变化计算得出的。 MC/MD演变的结构模仿了1800°C的退火处理，并在周期性方向上复制输出结构，以使较大的384000原子结构用于脱位模拟。由于SRC的形成，使用边缘位错来获得和解释，以获取和解释额外的增强。最后，MC/MD进化的含有位错的结构受到了CRS之外的高剪切应力，以研究位错和晶格结构的稳定性，以解释从tanbhfzr r-hea的实验观察到的从延性行为到脆性行为的过渡。
Refractory high entropy alloys (R-HEAs) are having properties and uses as high strength and high hardness materials for ambient and high temperature, aerospace and nuclear radiation tolerance applications, orthopedic applications etc. The mechanical properties like yield strength and ductility of TaNbHfZr R-HEA depend on the local nanostructure and chemical ordering. In this study we have computationally obtained various properties of the TaNbHfZr alloy like the role of configurational entropy in the thermodynamic property, rate of evolution of nanostructure morphology in thermally annealed systems, dislocation simulation based quantitative prediction of yield strength, nature of dislocation movement through short range clustering (SRC) and qualitative prediction of ductile to brittle transition behavior. The simulation starts with hybrid Monte Carlo/ Molecular Dynamics (MC/MD) based nanostructure evolution of an initial random solid solution alloy structure with BCC lattice structure created with principal axes along [1 1 1], [-1 1 0] and [-1 -1 2] directions suitable for simulation of 1/2[1 1 1] edge dislocations. Thermodynamic properties are calculated from the change in enthalpy and the configurational entropy by next-neighbor bond counting statistics. The MC/MD evolved structures mimic the annealing treatment at 1800°C and the output structures are replicated in periodic directions to make larger 384000 atom structures used for dislocation simulations. Edge dislocations were utilized to obtain and explain for the extra strengthening observed because of the formations of SRCs. Lastly the MC/MD evolved structures containing dislocations are subjected to a high shear stress beyond CRSS to investigate the stability of the dislocations and the lattice structures to explain the experimentally observed transition from ductile to brittle behavior for the TaNbHfZr R-HEA.
