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Effect of
Tempering on Thermal Analysis of AI-Ti-Si Alloy and Its
Composites |
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The
investigation of the effect of tempering on thermal analysis of
Al-Ti-Si alloy and its composites with MgO and SiC particles was
performed. Thermal analysis was performed before and after
tempering by DSC scan. Optical microscopy was used to identify
the phases and precipitations that may be formed in base alloy
and composites. X-ray diffraction test indicated that the Al3Ti
is the main phase in Al-Ti-Si alloy in addition to form
Al5Ti7Si12 phase. Some chemical reactions can be occurred
between reinforcements and matrix such as MgO.Al2O3 in
Al-Ti/MgO, and Al4C3 and Al(OH)3 in Al-Ti/SiC composite. X-ray
florescence technique is used to investigate the chemical
composition of the fabricated specimens. Heat treatment
(Tempering) changes the microstructure of base alloy and its
composites which was assessed by DSC scan. Generally, three main
peaks appeared in DSC represented by GP zone, S phase
(precipitations) and dissolution of phases or precipitations.
After tempering, composite with SiC particles showed better
results than base alloy and composite with MgO. Since the
optical microscopy revealed reforming the stable phase Al3Ti
with evaporation some gases from composite. DSC analysis showed
the stability of composite with SiC was up to 270oC. |
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