Growth dynamics of the segregated phase in Zn-6 wt%Bi immiscible alloy superheated in super high static magnetic field

Eliminating phase segregation under high temperature at high growth rate remains a long term challenge. Methods such as adding third element, inoculations and nanoparticle bring materials pollution and difficulties for compatibility. This work provides a path to realize a diffusional growth through extremely reducing the size of the segregated phase by highly superheating the system and suppressing their collision and coagulation via magnetohydrodynamic effect in Zn-6 wt%Bi immiscible system. The application of super high static magnetic field (SHSMF) compounded with superheating technique resulted in a homogeneous distribution of phase concentrated to about 3–4 µm when increased the magnetic flux density (MFD) from 0 T to 24 T and the superheating temperature from 600 °C to 900 °C. The undercooling of monotectic reaction was improved about 5–6 times from 0.4 °C to 2.1 °C when increased the super heating temperature from 600 °C to 900 °C with and without SHSMF. Bi-rich droplets grow as a near pure diffusion way when the particle size distribution follows the near LSW theory at 24 T. SHSMF has not only suppressed the mass transport of Bi atom but also decreased the size of Bi-rich clusters and even suppressed the precipitation of Bi-rich phases. The practicality has been proved by the same immiscible system with a critical composition. This novel method overcomes the microstructure refinement limit only through adding the extraneous and contaminated elements and realizes a contactless green way for growth control of phase. It has practical significance and is opening for expanding its scope of applications.