Date of Award
5-16-2024
Publication Type
Thesis
Degree Name
M.A.Sc.
Department
Mechanical, Automotive, and Materials Engineering
Keywords
Al Alloy 6451;Automotive closure;Corrosion;Mechanical properties;Microstructure
Supervisor
Henry Hu
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Abstract
A stamped Al Alloy 6451 containing 0.75 wt% Si used for outer panels of automotive body closures was tested for mechanical performance by comparing uncorroded and corroded specimens subjected to immersion corrosion following exposure to a 5.5 wt% NaCl saltwater solution. The mechanical properties including ultimate tensile strength (UTS), yield strength (YS) and elongation (ef) were evaluated by tensile testing. Following the exposure to a 5.5 wt% NaCl saltwater solution, the stamped alloy 6451 exhibited a significant decrease of both its UTS and YS to 141.82 and 70.02 MPa from 161.54 and 86.82 MPa, by 12.2 % and 19.4 %, respectively. Similarly, the ef of the Al alloy decreased to 14.62 % from 16.23 % by 9.9 %. The microstructure observation indicated that the presence of corrosion pits on the surface of the corroded alloy might promote the crack initiation and growth. The second group of samples was used to study the effect of NaCl Concentration on microstructure and mechanical properties following exposure to a 5.5 wt% NaCl saltwater solution and 3.5wt% NaCl saltwater solution for 28 days. Following the exposure to a 3.5 wt% NaCl saltwater solution and 5.5 wt% NaCl saltwater solution, the stamped alloy 6451 exhibited a very minimal decrease of both its UTS and YS to 145.62 and 69.04 MPa compared to 141.82 and 70.02 MPa, by 2.6 % and 1.4 %, respectively. Similarly, the ef of the Al alloy decreased very slightly to 14.62 % from 15.34 %, by 4.7 %. But, the tensile properties of the corroded samples were reduced significantly compared to those of the uncorroded alloy. The microstructure observation indicated that the presence of corrosion pits on the surface of the corroded alloy might promote the crack initiation and growth for both the specimen immersed in the 3.5 wt% and 5.5 wt% NaCl solution.
Recommended Citation
Abdul, Moiz, "Corrosion Effect on Microstructure and Mechanical Properties of Wrought Stamped Al Alloy 6451" (2024). Electronic Theses and Dissertations. 9415.
https://scholar.uwindsor.ca/etd/9415