On prominent TRIP effect and non-basal slip in a TWIP high entropy alloy during high-pressure torsion processing
On prominent TRIP effect and non-basal slip in a TWIP high entropy alloy during high-pressure torsion processing
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DOI：
10.1016/j.matchar.2021.111284
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发表时间：
2021-08
影响因子：
4.7
通讯作者：
A. Chandan;P. Hung;K. Kishore;M. Kawasaki;J. Chakraborty;J. Gubicza
中科院分区：
文献类型：
--
作者：
A. Chandan;P. Hung;K. Kishore;M. Kawasaki;J. Chakraborty;J. Gubicza
研究了面心立方 (FCC) 孪生诱导塑性 (TWIP) 高熵合金 (HEA) Fe40Mn40Co10Cr10 在高压扭转 (HPT) 作用下的剧烈塑性变形响应。即使在 1/2 圈（剪切应变，γ=15）HPT 加工中，所谓的 TWIP HEA 也表现出广泛的相变诱导塑性 (TRIP) 效应，并且随着圈数增加到 2 (γ=68)，这种效应进一步增强。此外，HPT 诱导纳米结构和严重位错结构；位错密度约为1015m−2。发现转化的 HCP 相的 c/a 比率<1.633，并且它不随剪切应变程度的增加而变化。这表现为在 HCP 相中发生至少 50% 的非基底滑移。首次量化了位错和<c+a>位错的比例，并在所研究合金的范围内讨论了它们的演化。应变调节的微观机制与连续 HPT 处理后 HEA 硬度的增加相关。目前的工作提供了一种观点，即亚稳态 FCC HEA 中变形诱导的 HCP 相可以具有定制的 c/a 比率，从而触发非基底滑移，从而产生坚固且具有延展性的材料。
Severe plastic deformation response of a face centered cubic (FCC) twinning induced plasticity (TWIP) high entropy alloy (HEA), Fe40Mn40Co10Cr10, subjected to high-pressure torsion (HPT) is investigated. The so-called TWIP HEA demonstrated an extensive transformation induced plasticity (TRIP) effect even in ½ turn (shear strain,γ= 15) of HPT processing, which increased further with increasing the number of turns to 2 (γ= 68). Additionally, HPT induced nano-structuring and heavily dislocated structure; dislocation density was of the order of 1015m−2. c/a ratio of the transformed HCP phase was found to be <1.633 and it did not change with increasing the extent of shear strain. This was manifested as the occurrence of at least 50% non-basal slip in the HCP phase. For the first time, the fraction of and <c+a> dislocations are quantified and their evolution are discussed in the purview of the studied alloy. The micro-mechanism of strain accommodation is correlated with increasing hardness of the HEA upon sequential HPT processing. The present work provides a viewpoint that the deformation induced HCP phase in a metastable FCC HEA can have tailored c/a ratio which triggers non-basal slip, leading to a strong and ductile material.