Date of Award

1-10-2023

Publication Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Eutectic Al alloy

Supervisor

H.Hu

Supervisor

N.Eaves

Rights

info:eu-repo/semantics/openAccess

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

A eutectic Al Alloy containing 1.8 wt.% Fe was cast by using a permanent steel mold casting (PMSC) with three different section thicknesses of 2, 8, 20 mm, and also squeeze cast (SC) with a cross-sectional thickness of 20 mm under an applied pressure of90 MPa. First, the difference in mechanical and electrical properties between the PSMC eutectic Al-1.8Fe Alloy and commercial-purity (CP) Al (99.7%) was investigated. The results showed that the ultimate tensile strength (UTS), yield strength (YS) of the cast CPAl significantly increased to 86.5 and 28.3 MPa from 34.5 and 12.3 MPa. However, the elongation (ef) and electrical conductivity (σ) of the cast alloy decreased to 19.8% and48.4 %IACS from 33.8% and 58.5 %IACS. The large area fraction (9.5%) of the micron and nano eutectic Al-Fe phases in the PSMC Al-1.8%Fe alloy should be responsible for the difference in mechanical and electrical properties between the PSMC Al-1.8%Fealloy and the PSMC CP Al. Secondly, the effect of section thicknesses on microstructure, mechanical and electrical properties of the PSMC Al-1.8Fe alloy was studied. The UTS,YS, ef, and elastic modulus (E) of the alloy increased, when the section thickness of the PSMC Al-1.8Fe decreased to 2 mm from 20 mm. However, the porosity level increased to 1.87% from 5.17% with increasing the thickness to 20 mm from 2 mm, respectively. The fine microstructure and low porosity level resulted in the high properties of the 2 mm sample. The study on the SC alloy indicated that the casting process increased the properties. The strain-hardening rate of the SC Al-1.8Fe alloy during plastic deformation was higher than that of the PSMC specimen. The high mechanical properties and electrical conductivities of the SC sample should be attributed to its fine microstructure and low porosity level compared to that of the PSMC counterpart.

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