超声处理诱导组织细化提升Ti1.5NbZrV0.4Mo0.6Si0.6高熵合金强塑性机制OA

This study systematically investigated the effects of ultrasonic treatment time(0-120 s)on the microstructure and mechanical properties of Ti1.5NbZrV0.4Mo0.6Si0.6 high-entropy alloy.Alloy specimens were prepared via vacuum arc melting combined with ultrasonic field treatment.The phase composition,microstructural evolution,and mechanical properties of the alloy were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS),and room-temperature compression tests.The results indicated that ultrasonic treatment did not alter the dual-phase composition of BCC and Zr3Ti2Si3 silicide in the alloy but significantly improved the uniformity of element distribution.The content of the BCC phase decreased from 70.4%to 54.5%,while the content of the silicide phase increased from 29.6%to 45.5%.Microstructural analysis revealed that ultrasonic treatment promoted the transformation of BCC dendrites into clustered morphology,increased the proportion of eutectic structure to 93.0%,and refined the lamellar spacing from 3.7 μm to 0.93 μm(with a refinement degree of 75%).In terms of mechanical properties,the yield strength of the alloy increased to 1 762 MPa,the compressive strength reached 2 108 MPa,and the fracture strain increased by 66.3%,achieving a synergistic optimization of strength and plasticity.Fractography analysis further revealed a transition in the fracture mechanism from intergranular fracture to cleavage fracture.This study elucidates the synergistic effects of ultrasonic cavitation and acoustic streaming,which promote nucleation,suppress segregation,and refine eutectic lamellae through multiple mechanisms.It provides theoretical insights and process references for the solidification control of high-performance high-entropy alloys.