Abstract
Aluminium Matrix Composites (AMCs) reinforced with Al2O3 nano particles are widely used for
high performance application such as aerospace because aluminium is light weight and alumina has
good performance at high temperature. Alumina nano particles is added into molten Al with different volume
fraction from 0.2 vf-% to 1.2 vf-% while Mg is used as an external dopant with 10 wt-% to promote
wetting between aluminium and Al2O3. The Al alloy was then melted and Mg along with the reinforcement
was blended inside the molten metal by stirrier with rotational speed of 500 rpm at 800oC for 2 minutes
and degassing with Ar for 4 minutes to remove all of gas in molten Al. The molten composites then was
casted into plate and tensile test sample molds. The effect of Al2O3 nano particles on mechanical properties
and microstructure of composites was investigated. The optimum tensile strength, hardness and elongation
of composite was achieved at additon of 0.2vf-% Al2O3np with the value of 220 MPa, 61 HRB and 5.48%
respectivelly. Increasing hardness was caused by impedation of dislocation movements by nano-Al2O3
particles. It is found that the addition of more Al2O3np, the mechanical propeties decreased. The
microstructure observations showed that the composites yield finer grains than the unreinforced alloy
Addition of nano-Al2O3 particles also tend to form microporosity and agglomeration which would decrease
the tensile strength of composites.
Original language | English |
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Pages (from-to) | 39-47 |
Journal | International Journal of Materials Science and Engineering |
Volume | 6 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Jun 2018 |
Keywords
- Aluminium composites, Al2O3 nano particles, mechanical properties, stir casting process.