The effects of mg addition on the microstructure and mechanical properties of Thixoformed Al-5%Si-Cu alloys
In this study, the effects of different amounts of magnesium (Mg) on the microstructures and tensile properties of thixoformed Al–5%Si–Cu alloys were investigated. Three different alloys containing various amounts of Mg (0.5, 0.8 and 1.2 wt%) were prepared through the cooling slope casting techniq...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | en |
| Published: |
Elsevier
2014
|
| Subjects: | |
| Online Access: | http://eprints.utem.edu.my/id/eprint/14309/1/The_effects_of_Mg_addition_on_the_microstructure_and_mechanical_properties_of_thixoformed_Al-5%25Si_alloys.pdf http://eprints.utem.edu.my/id/eprint/14309/ http://www.elsevier.com/locate/jalcom |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | In this study, the effects of different amounts of magnesium (Mg) on the microstructures and tensile
properties of thixoformed Al–5%Si–Cu alloys were investigated. Three different alloys containing various
amounts of Mg (0.5, 0.8 and 1.2 wt%) were prepared through the cooling slope casting technique, before
they were thixoformed using a compression press. Several of the thixoformed samples were then treated
with a T6 heat treatment, that is, solution treatment at 525 C for 8 h, quenching in warm water at 60 C,
followed by aging at 155 C for 4 h. All of the samples were then characterised by optical microscopy
(OM), scanning electron microscopy (SEM) energy dispersive X-ray (EDX) spectroscopy and X-ray
diffraction (XRD) analysis as well as by tensile tests. The results revealed that magnesium was able to
refine the size of a-Al globules and the eutectic silicon in the samples. It was also observed that a compact
p-Al9FeMg3Si5 phase was formed when the magnesium content was 0.8 wt% and 1.2 wt%. The mechanical
properties of the thixoformed alloys improved significantly after the T6 heat treatment. The highest
attainment was recorded by the latter alloy (i.e. with 1.2 wt%Mg) with its ultimate tensile strength
(UTS) as high as 306 MPa, yield strength (YS), 264 MPa, and elongation to fracture of 1.8%. The fracture
of thixoformed alloy with a low Mg content (0.5 wt%) showed a combination of dimple and cleavage
fracture, whereas in the alloy that contained the highest Mg content (1.2 wt%), cleavage fracture was
observed. |
|---|