Author: Johann Jordaan
Jordaan, Johann, 2023 Effect of inter-pass temperature on the fatigue properties of wire-arc additively manufactured aluminium 5183, Flinders University, College of Science and Engineering
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Wire-arc additive manufacturing is an upcoming technology that allows for free-form, near
net shape manufacturing of large components using a welding process. This process is
rapidly becoming a more efficient way to produce complex components using available
welding wire. Due to its common use in critical industries that require large and complex
parts, aluminium is a promising material for use in the additive manufacturing industry.
The critical nature of these components, however, require extensive knowledge of material
properties such as tensile strengths and fatigue behaviour – which is currently very limited.
Optimisation of parameters such as inter-pass temperature has been proposed to improve
deposited material quality, but the relationship between inter-pass temperature and
mehcnaicl and fatigue properties is not well understood. Furthermore, due to the significant
effect of build direction on WAAM materials, specimen orientation was also considered.
Using AML3D’s proprietary WAM manufacturing technique, test pieces were produced using
aluminium alloy 5183 at inter-pass temperatures of 100oC and 150oC. Tensile, hardness
and fatigue testing were then completed, along with microstructural assessments, fatigue
fractography and elemental analysis.
Inter-pass temperature was shown to have no significant effect on tensile or hardness
properties, with reported yield and ultimate tensile strengths of 129.5 and 272.8 MPa
respectively. The increased inter-pass temperature did however have a noticeable effect on
fatigue life, with low-medium cycle fatigue life showing an increase of approximately 20%.
Build direction was shown to have no significant effect on tensile properties but showed a
noticeable effect on both hardness and fatigue life. Metallographic examination and fatigue
fractography highlighted large amounts of internal porosity, with most fatigue fractures
initiating at sites of porosity.
The increased inter-pass temperature resulted in an approximate 43% increase in
production efficiency, highlighting the potential benefits of optimising the inter-pass
temperature. The presence of internal defects, however, need to be closely monitored as
these initiate the majority of failures. Further work investigating the effect of inter-pass
temperature and welding process on porosity is suggested, while continuing to optimise
production efficiency of the WAAM process.
Keywords: aluminium, aluminium alloy, 5183, additive manufacturing, wire-arc additive manufacturing, WAAM, fatigue, fatigue testing, material properties, material testing
Subject: Engineering thesis
Thesis type: Masters
Completed: 2023
School: College of Science and Engineering
Supervisor: Dr. Reza Hashemi