| Summary: |
The performance of a mechanical component is often conditioned and limited by the characteristics of the materials themselves, as well as by limitations and restrictions of the manufacturing processes. The most suitable and economically advantageous manufacturing technologies for a specific application are frequently incompatible with the most suitable materials for that application, and make it impossible the explanation of those solutions developed/created by the product development engineering. As an example, we can refer the difficulty inherent to the casting of thin wall parts in alloys with poor castability, like some steel grades.
This project appears as a consequence of the research work developed by some members of the research team on the aim of a project developed in cooperation with an industrial partner, supported by Agência de Inovação, dedicated to the recycling of aluminium swarf by casting. The results of that project revealed that the efficiency of the present liquid metal treatment techniques - degassing, eutectic silicon modification and grain refinement - is very low, and do not avoid a number of problems that are critical for the application of aluminium castings in applications where mechanical resistance is a crucial factor. Among other problems, the present techniques frequently lead to heterogeneous chemical composition, deficient microstructure morphology and porosities. As a consequence of those anomalies, mechanical properties are frequently insufficient for applications where high strength-to-weight ratio is required, like applications in biomechanics and in the aeronautical and automotive industries, where not only the casting sanity is critical, but the need to use thin wall high strength castings is an imperative. On the other hand, the present metal treatment techniques are an important source of residues, like slag, with important environmental impact.
On this work, alternative metal treatment techniques, base  |
Summary
The performance of a mechanical component is often conditioned and limited by the characteristics of the materials themselves, as well as by limitations and restrictions of the manufacturing processes. The most suitable and economically advantageous manufacturing technologies for a specific application are frequently incompatible with the most suitable materials for that application, and make it impossible the explanation of those solutions developed/created by the product development engineering. As an example, we can refer the difficulty inherent to the casting of thin wall parts in alloys with poor castability, like some steel grades.
This project appears as a consequence of the research work developed by some members of the research team on the aim of a project developed in cooperation with an industrial partner, supported by Agência de Inovação, dedicated to the recycling of aluminium swarf by casting. The results of that project revealed that the efficiency of the present liquid metal treatment techniques - degassing, eutectic silicon modification and grain refinement - is very low, and do not avoid a number of problems that are critical for the application of aluminium castings in applications where mechanical resistance is a crucial factor. Among other problems, the present techniques frequently lead to heterogeneous chemical composition, deficient microstructure morphology and porosities. As a consequence of those anomalies, mechanical properties are frequently insufficient for applications where high strength-to-weight ratio is required, like applications in biomechanics and in the aeronautical and automotive industries, where not only the casting sanity is critical, but the need to use thin wall high strength castings is an imperative. On the other hand, the present metal treatment techniques are an important source of residues, like slag, with important environmental impact.
On this work, alternative metal treatment techniques, based in the use of ultrasonic energy to perform degassing and microstructure modification and refinement in different stages of the processing cycle, will be developed. The effect of the process variables in the efficiency of the developed technique will be studied, by characterizing the hydrogen removal capability as well as the effect of ultrasonic oscillation on the grain refinement and eutectic silicon modification. Moreover, the effect of ultrasonic oscillation in the alloy castability will be studied, by characterizing and evaluating its influence in the filling of thin wall castings and complex geometries.
This work will include the development of laboratory scale casting unit for ultrasonic metal treatment and will identify the range of applicable process parameters for industrial implementation of the technology. |