Pham T N, Ohno K, Sahara R, Kuwahara R, Bhattacharyya S
Department of Physics, Yokohama National University, 79-5 Tokiwadai, Yokohama 240-8501, Japan.
J Phys Condens Matter. 2020 Jun 17;32(26):264001. doi: 10.1088/1361-648X/ab7ad5.
Ti-6 wt% Al-4 wt% V (Ti64) is an α + β titanium alloy, in which the alloying components strongly affect the mechanical properties. In this report, element partitioning effects in Ti64 are investigated by using the first-principles phase field (FPPF) method, which has recently been proposed by our group. In the FPPF method, the local free energy is calculated using a cluster expansion method in combination with density functional theory and the temperature effect is incorporated using potential renormalization theory. We have succeeded in identifying enrichment of Al (V) in the α (β) phase, i.e., the clear evidence for the element partitioning effects of Al and V, without using any thermodynamical parameter. The transformation of the β phase and the α phase in microstructure is investigated by varying the V and Al concentrations by a small amount. Our results are in excellent agreement with the recent experimental results, showing the validity of the FPPF method for ternary alloys.
Ti-6重量百分比Al-4重量百分比V（Ti64）是一种α+β钛合金，其中合金成分对机械性能有强烈影响。在本报告中，采用我们团队最近提出的第一性原理相场（FPPF）方法研究了Ti64中的元素偏聚效应。在FPPF方法中，使用簇展开方法结合密度泛函理论计算局部自由能，并使用势重整化理论纳入温度效应。我们成功地确定了α（β）相中Al（V）的富集，即Al和V元素偏聚效应的明确证据，而无需使用任何热力学参数。通过少量改变V和Al浓度来研究微观结构中β相和α相的转变。我们的结果与最近的实验结果非常吻合，表明FPPF方法对三元合金的有效性。
