Metal Processing Institute
Advanced Casting Research Center

Research Programs

Quantitative Microstructure Characterization of Commercial Semi-Solid Aluminum Alloys


Research Team:

Qingyue Pan
Diran Apelian

Introduction

The rheological properties of semi-solid metal slurries are strongly dependent on their microstructure. Specifically, three characteristic microstructural parameters are critical in determining rheological behavior and flow properties of aluminum semi-solid slurries. They are: (1) particle size of the Alpha phase; (2) shape factor of the Alpha particles, and (3) entrapped liquid content within the Alpha particles. In this work, extensive image analyses have been performed to determine evolution of the three parameters as a function of commercial processing conditions and material genealogy. Semi-solid materials evaluated include MHD, GR, SIMA, new MIT, and UBE processed billets, and processing conditions investigated include different processing temperatures during continuous heating, as well as isothermal holding for different times at commercial forming temperatures. In addition, detailed investigations were carried out to reveal the formation mechanism of the entrapped liquid within the Alpha phase.

Objectives

The aim of this project was to establish a comprehensive knowledge base in understanding the effect of processing conditions and material genealogy on the microstructure evolution and rheological properties of various semi-solid metal slurries. Quantitative data have been provided to optimize industrial practice

Salient Results

Salient results of this study are highlighted below:

SSM Related Publications

Related Publications

Figure 1: As-cast microstructure of various semi-solid billets.

Figure 2: Semi-solid microstructure of various semi-solid billets at 580°C.

Figure 3: Evolution of shape factor as a function of processing temperature and material genealogy.

Figure 4: Evolution of particle size as a function of processing temperature and material genealogy.

Figure 5: Evolution of entrapped liquid as a function of processing temperature and material genealogy.

Figure 6: Evolution of entrapped liquid as a function of isothermal holding time and material genealogy.

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Last modified: September 11, 2007 16:06:03