The compositional possibilities in high entropy alloys (HEAs) is very vast and effective strategies are needed to establish potential alloy chemistries. In this study, friction stir gradient alloying (FSGA), a recently-introduced high-throughput (HT) technique incorporating compositional and microstructural gradients, was used to explore the possibility of introducing a bcc transformation domain in γ-fcc dominated TRIP HEA Fe_38.5Mn₂₀Cr₁₅Co₂₀Si₅Cu_1.5 (at.%) by vanadium addition. FSGA has accelerated the process of attaining the composition-microstructure library and the results suggest that vanadium addition of ~1 at.% results in nucleation of α-bcc. This is the first observation of ε-hcp to α-bcc transformation in a TRIP HEA and supports the Olson-Cohen model of martensitic transformation (γ-fcc → ε-hcp → α-bcc). ε-hcp is nucleated with a pyramidal orientation by the formation of planar faults on the {111} close-packed planes of γ-fcc, and α-bcc is nucleated in the vicinity of ε-hcp along the {111} γ-fcc trace. There are indications for the formation of basal orientated ε-hcp from intersecting ε-hcp planes orientated for the pyramidal slip. Thus, the study shows the nucleation and growth of the α-bcc phase attributed to the dual effects of chemistry and strain and potential co-existence of all the three phases.

高熵合金（HEA）的成分可能性非常广泛，需要有效的策略来建立潜在的合金化学性质。在这项研究中，摩擦搅拌梯度合金（FSGA）是一种最近引入的结合成分和微观结构梯度的高通量（HT）技术，用于探索在以γ-fcc为主的TRIP HEA Fe _38.5中引入bcc转变域的可能性Mn ₂₀ Cr ₁₅ Co ₂₀ Si ₅ Cu _1.5（at。％）通过添加钒。FSGA加速了获得组成-微观结构库的过程，结果表明〜1 at。％的钒添加量会导致α-bcc成核。这是在TRIP HEA中从ε-hcp到α-bcc转变的首次观察，并支持马氏体转变的Olson-Cohen模型（γ-fcc→ε-hcp→α-bcc）。ε-hcp通过在γ-fcc的{111}紧密堆积平面上形成平面断层而以金字塔取向成核，并且α-bcc在{-111}γ-fcc的ε-hcp附近成核。跟踪。有迹象表明，由面向锥体滑移的相交的ε-hcp平面相交可形成基底取向的ε-hcp。从而，