Study on Microstructure of Semi-Solid Magnesium Alloy Manufactured by Gas Bubbles Stirring

Abstract

The semi-solid slurry of AZ31 magnesium alloy was manufactured by gas bubbles stirring. The effects of stirring temperature and stirring time on the microstructure of semi-solid slurry were researched. The results indicate that it is feasible to manufacture the slurry with particle-like primary phases. When the stirring temperature is higher, the morphology of the primary a-Mg presents rosette-like morphology and the size of grain is coarse, and the morphology mainly was α- Mg dendrite at lower stirring temperature. Long stirring time could reduce dendrites and liquid phase, and made the non-dendritic grains well spheroidized. But the effects of longer stirring on shape and size of primary particles are not significant. The optimal process parameters for ideal semi-solid slurry manufactured were stired 3min at 645°C.

Design and Numerical Simulation of a Gas Mixer

“…The mixing can be regarded as uniform when the value of the heterogeneous degree is smaller than 0.05 or the value of the mixing uniformity is larger than 95 % [20]. In order to calculate the heterogeneous degree of the distribution of carbon monoxide concentration at the mixer's outlet, the concentration of carbon monoxide at some special points should be considered, such as the center of the outlet, the points on the circumference of the mixer's outlet.…”

Effects of Process Parameters on Microstructure and Mechanical Properties of Semi-Solid Al-7Si-0.5Mg Aluminum Alloy by Gas Induced Semi-Solid Process

“…There are many studies on the parameters such as the starting ventilation temperature, rotation speed, ventilation time and ventilation flow in the GISS method [20][21][22]. However, there is not much research on the effects of holding time and medium alloy addition on the microstructure evolution, although they have a great influence on the spheroidization and refinement process of the slurry.…”