0.25Cr0.25Ni0.25Mn0.25中熵合金在900~1050 ℃、0.001~1 s-1應(yīng)變速率范圍內(nèi)的流變行為。結(jié)果表明，熱變形以動態(tài)再結(jié)晶為主，與其他低堆垛層錯(cuò)能的合金一樣，流變曲線呈單峰形狀。建立了本構(gòu)模型來描述整個(gè)變形過程，分析了加工硬化行為和動態(tài)軟化過程。利用Kocks-Mecking圖發(fā)現(xiàn)，在加工硬化階段，合金的硬化速率隨應(yīng)力呈線性降低，因此應(yīng)力-應(yīng)變行為可以用傳統(tǒng)的位錯(cuò)密度模型來描述。同時(shí)，采用經(jīng)典的JMAK方程描述由動態(tài)再結(jié)晶引起的軟化過程。此外，對本構(gòu)模型進(jìn)行了進(jìn)一步的修改，減少了參數(shù)的數(shù)量，簡化了回歸分析。所提出的半物理模型不僅可以準(zhǔn)確地預(yù)測應(yīng)變范圍外的應(yīng)力-應(yīng)變行為，而且可用于其他低層錯(cuò)能合金。;The flow behavior of a medium entropy alloy with a nominal composition of Fe0.25Cr0.25Ni0.25Mn0.25 was analyzed by isothermal compression performed in the temperature range of 900~1050 °C and strain rate range of 1~0.001 s-1. The results show that the hot deformation is predominated by dynamic recrystallization, so that the flow curves exhibit a single-peak shape as those of other alloys with low stacking-fault energy. Particular emphasis was paid to develop a simple constitutive model which can describe the entire deformation history. For this purpose, the work-hardening behavior as well as the dynamic softening regime were analyzed. With the aid of Kocks-Mecking plots, it is found that the hardening rate of the present alloy is linearly decreased with stress in the work-hardening stage, and hence the stress-strain behavior can be described by the conventional dislocation density-based model. Meanwhile, the softening regime, which is caused by dynamic recrystallization, can be modelled by the classic JMAK equation. Besides, the model is further modified to reduce the number of parameters and simplify the regression analysis. The proposed semi-physical based model can not only accurately predict the stress-strain behavior to strain levels outside the experimental strain range, but can also be promoted to other alloys with low stacking-fault energy."/>