Date of Award

2007

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Materials Science and Engineering

Supervisor

David S. Wilkinson

Co-Supervisor

Mukesh Jain

Language

English

Abstract

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The production of aluminum sheet material can follow two distinct processing routes: the conventional semi-continuous process referred to as direct-chill (or DC) casting and, more recently, the continuous casting process (CC). The variation in processing routes can affect the alloy's microstructure, specifically in terms of particle size distribution and the concentration of alloying elements in solid solution, which can alter the materials mechanical properties. Therefore, the formability and fracture behaviour of AA5754 automotive sheet material in the O-temper, produced via two different processing routes, CC and DC casting, has been investigated by the use of the forming limit diagram (FLD).

An in-plane forming test, developed by Marciniak (1973) was used to determine p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times; color: #202020} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times; color: #383838} span.s1 {color: #383838} span.s2 {color: #525252} span.s3 {color: #6c6c6c} span.s4 {color: #202020}

the intrinsic forming limits of the two materials, while full-field strain mapping based on

digital image correlation analysis was used to follow the inhomogeneous plastic flow

behaviour. As a result, PLC deformation bands were observed and their influence as

geometric imperfections to initiate premature failure was shown to be dependent on the

strain path. In addition, post-necking and fracture observations were used to understand

the influence of microstructural variations and inhomogeneities on the total ductility of

AA5754, in terms of the two processing routes.

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