The evaluation of microporosity and mechanical properties in high strength aluminum alloys with the use of numerical analysis and computed tomography

One of the aspects of sustainable development is the reduction of the concentration of CO₂ in the atmosphere. This could be achieved for example by the reduction of fuel consumption. That is why the research for the new construction and material solutions regarding the reduction of the weight of vehicles is so important. Alongside weight reduction of different kinds of vehicles, there is also the possibility of the application of alternative propulsion systems. The lower total vehicle weight allows to extend the lifetime of the batteries with the reduction of recharge cycles. The use of the aluminum base AlZnMgCu as cast alloy which is known as 7xxx series plastic forming alloy, allows to significantly reduce the weight of the components manufactured as cast structures, ensuring high strength properties. The wide range of the solidification temperature, which is more than 150°C, characterizes this alloy with a high tendency to create micro and macro porosity. The study presents the relationship between the cooling rate and the area of occurrence and percentage of microporosity. Obtained results were linked to the local tensile strength predicted in the simulation analysis. The evaluation of the microporosity was performed on the basis of the CT (computed tomography) and the analysis of the alloy microstructure. The microstructure analysis was carried out on a test specimen obtained from the varying wall thickness of the experimental casting. The evaluation of the mechanical properties was conducted on the basis of the static tensile test.

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