Papers by Author: S. Ashouri

Abstract: Continual improvement of product quality has been a long challenge to Semi-Solid Metal (SSM) technology. By conventional semi-solid processes, this might be attained at the expense of economical production. The advent of Inclined Cooling Plate (ICP) process has already realized the development of non-dendritic SSM while satisfying qualitative, quantitative and economical requirements collectively. In spite of its potential advantages, functional mechanisms of this process are not yet clearly understood that makes its optimal utilization obscured. Basically, such understanding needs a picture of the process. As the first step, this picture is pursued through physical modeling of the ICP process i.e. direct observation of an analog system by virtue of transparent character of a model alloy (succinonitrile-acetone). Based on this phenomenological model, a picture of the process is presented as follows: flowing molten alloy down ICP, multiple regions form typically on the plate i.e. a chilled layer at the vicinity of the plate surface, a two-phase mushy zone on the chilled layer and ambient liquid far from the plate surface. In this process, interaction of the liquid forced-flow with mushy zone separates solid particles from the stationary mush on the plate resulting in a two-phase mixture which is responsible for the formation of slurry i.e. SSM.

Abstract: Semi-solid forming (SSF) involves alloys with non-dendrite microstructure that contain spherical solid particles in the liquid matrix. This process is generally divided into three main steps: feedstock manufacturing, reheating and forming. Feedstock has the main effect on the cost and quality of product. Many researches have been carried out to reduce the cost of feedstock manufacturing. Slope plate is a simple semi-solid process that can reduce the cost of feedstock. In this study a Cu plate with water and without water circulation was used to investigate the effect of pouring temperature, cooling rate during casting and solidification in the mold on the microstructure. Cast ingots with optimized microstructure were reheated in various time and temperatures in semi-solid region to obtain kinetics of globularization and solid grain growth.