The aim of this study was to produce partially reinforced aluminum metal matrix
composite components by insertion casting technique and to determine the effects
of silicon content, fiber vol% and infiltration temperature on the mechanical
properties of inserts, which were the local reinforcement parts of the components.
Silicon content of alloys was selected as 7 wt% and 10 wt%. The reinforcement
material, i.e. Saffil fiber preforms, had three different fiber vol% of 20, 25 and 30
vol% respectively. The infiltration temperatures of composite specimens were fixed
as 750 ° / C and 800 ° / C.
In the first part of the thesis, physical and mechanical properties of composite
specimens were determined according to the parameters of silicon content of the
matrix alloy, infiltration temperature and vol% of the reinforcement phase. X-ray
diffraction examination of fibers resulted as the fibers mainly composed of deltaalumina
fibers and scanning electron microscopy analyses showed that fibers had planar isotropic condition for infiltration. Microstructural examination of
composite specimens showed that appropriate fiber/matrix interface was created
together with small amount of micro-porosities. Bending tests of the composites
showed that as fiber vol% increases flexural strength of the composite increases.
The highest strength obtained was 880.52 MPa from AlSi10Mg0.8 matrix alloy
reinforced with 30 vol% Saffil fibers and infiltrated at 750 ° / C. Hardness values
were also increased by addition of Saffil fibers and the highest value was obtained
as 191 HB from vertical to the fiber orientation of AlSi10Mg0.8 matrix alloy
reinforced with 30 vol% Saffil fibers. Density measurement revealed that microporosities
existed in the microstructure and the highest difference between the
theoretical values and experimental values were observed in the composites of 30
vol% Saffil fiber reinforced ones for both AlSi7Mg0.8 and AlSi10Mg0.8 matrix
alloys.
In the second part of the experiments, insertion casting operation was performed.
At casting temperature of 750 ° / C, a good interface/component interface was
obtained. Image analyses were also showed that there had been no significant fiber
damage between the insert and the component.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12610751/index.pdf |
| Date | 01 July 2009 |
| Creators | Turkyilmaz, Gokhan |
| Contributors | Kalkanli, Ali |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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