Investigation on Microstructure Control and Mechanical Properties of Directionally-Solidified FCC/B2 Dual-Phase High-Entropy Alloy
In this study,the microstructures of the directionally solidified FCC/B2 dual-phase high-entropy alloy were tailored based on different heat treatment processes to improve the mechanical properties in a wide temperature range.The microstructure evolution mechanism under different heat treatment regimes was clarified,and the influence of microstructures on the mechanical properties of the alloy was analyzed.The results show that high-density near spherical L12 precipitates can be obtained in the FCC matrix,while lath-like L12 precipitates can be obtained in the B2 phase after solution treatment followed by double aging at high-temperature 800℃and low-temperature 650℃.High-density precipitates effectively strengthen the alloy,and the L12 phase can promote dislocation movement in the B2 phase,which is beneficial to improve the plasticity of the alloy at the same time.Compared to the as-cast sample,the comprehensive high-temperature mechanical properties of the alloy after heat treatment are improved.
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