Evaluation of casting fluidity and filling capacity of Zr-based amorphous metal melts

Understanding the flow characteristics of amorphous metal melts is important for casting and molding processes. Fluidity of Zr-based amorphous metal melts was determined by using a self-designed apparatus. Phase analysis demonstrated that the fluidity test samples were fully amorphous structure. The onset crystallization temperature significantly moved toward high temperature with the increases of casting temperature, which improved the glass-forming ability and thermal stability of Zr-based amorphous metal. Fluidity test results demonstrated that the fluidity length increased monotonically with the increases of temperature, pressure, and runner diameter. By identifying the types and quantities of the defect in castings, it could conclude that smooth filling processes occurred under appropriate conditions. Experimental results indicated that the flow behavior of the Zr-based amorphous metal melts strongly depended on the casting temperature and equivalent thickness. Constitutive equation based on Newton’s law of heat exchange and Rayleigh rule was established to evaluate the fluidity of Zr-based amorphous metal melts. Theoretical calculations and experimental tests were basically coincided with each other. The determined optimal casting temperatures and equivalent thicknesses were adopted to successfully fabricate a series of fully shaped castings through gravity casting.