Casting and Analysis of Squeeze Cast Aluminium Silicon Eutectic Alloy

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Mechanical Engineering
Degree name
Doctor of Philosophy
Publisher
University of Canterbury. Mechanical Engineering
Journal Title
Journal ISSN
Volume Title
Language
Date
2006
Authors
Smillie, Matthew John
Abstract

Squeeze casting is the practise of solidifying metals under mechanically applied pressure via a slow displacement of a die volume. It has been shown that squeeze casting enhances the mechanical properties of cast metals. Research into other high integrity casting processes has shown that using techniques that enhance melt quality can further increase the mechanical properties. Therefore a bottom-tapped, bottom-fed squeeze casting machine was designed and built around a pre-existing squeeze casting die designed for uniaxial pressure application. This was used to obtain quantitative metallurgical and microstructural information on the squeeze castings produced, including the effects of common micro-alloying additions of strontium modifier and titanium modifier on the microstructure and hardness of a commercial aluminium silicon eutectic alloy. These were examined using a Taguchi design of experiments approach. It was found that squeeze casting reduced porosity and secondary dendrite arm spacing and increased hardness, and reduced or eliminated increases in porosity and secondary dendrite arm spacing associated with micro-alloying addition. The size of possibly deleterious iron-rich precipitates was reduced, and the morphology of such precipitates changed to a possibly less deleterious form without further alloy additions of manganese. It was also found that melt control and handling is essential for consistent quality of castings in the production of small volume squeeze castings, such as the ones produced in this experimental work.

Description
Citation
Keywords
Aluminium Silicon eutectic alloys, squeeze casting, bottom fed, porosity, dendrite arm spacing, secondary dendrite arm spacing, strontium modified, titanium modified, iron-rich precipitates
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
Copyright Matthew John Smillie