Date of Award

2024

Publication Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Supervisor

Henry Hu

Abstract

Wrought magnesium alloy AZ80 was produced using both squeeze casting (SC) and permanent steel mold casting (PSMC) with a 20 mm thick section. Porosity assessments showed SC AZ80 had 0.52% pore content, 77% lower than the 2.21% in PSMC AZ80. Mechanical properties were evaluated through tensile testing. SC AZ80 exhibited a yield strength (YS) of 84.7 MPa, ultimate tensile strength (UTS) of 168.2 MPa, elongation (ef) of 5.1%, and elastic modulus (E) of 25.1 GPa, while PSMC AZ80 had YS of 71.6 MPa, UTS of 109.0 MPa, ef of 1.9%, and E of 21.9 GPa. SC AZ80 outperformed PSMC AZ80 by 18% in YS, 54% in UTS, 174% in ef, and 15% in E. SC AZ80 also exhibited superior resilience and toughness, showing greater resistance to tensile forces and higher energy absorption capacity compared to PSMC AZ80. The strain-hardening rate at the onset of deformation was 10,341 MPa for SC AZ80, 9% higher than the 9,489 MPa for PSMC AZ80. These superior mechanical properties were attributed to the lower porosity of SC AZ80. Microstructure analysis using optical microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) revealed α-Mg and Mg-Al-Zn intermetallic phases in both alloys, with higher intermetallic content and smaller dendrite sizes in thinner PSMC walls (6 mm) compared to thicker ones (20 mm). Thinner walls exhibited improved tensile properties, linked to finer dendritic structures, higher intermetallic content, and reduced porosity. These results highlight the benefits of squeeze casting and reduced wall thickness in enhancing the mechanical properties of AZ80 alloy.

Download

Included in

Engineering Commons

Share

COinS