Solidification and properties of Al-Ni, Al-Cu-Ni, Al-Cu-Fe, and Al-Cu-Fe-Ni alloys with a focus on the characterization of intermetallic phases.

• Grant number: 23/13255-9
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: March 01, 2024
• End date: February 29, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: José Eduardo Spinelli
• Grantee: Felipe Escher Saldanha
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

In the recycling of Al alloys, it is common for residual impurities, especially Fe, to accumulate, often resulting in the formation of coarse intermetallic compounds during the solidification process. These intermetallics compromise the mechanical properties of the final product. Considering the high costs associated with reducing the Fe content and/or using thermomechanical processes to mitigate the formation of intermetallics, it is more advantageous to manipulate the morphology, size, and distribution of these phases during solidification. Therefore, advancements in the faceted growth of Fe-rich phases in Al-Cu alloys modified with Ni play a crucial role in refining the control of size, shape, and anisotropy (aspect ratio) under different solidification conditions. The results obtained can be valuable for generating morphologies that enhance the properties of alloys, making them more resistant to Fe contamination and, consequently, promotingthe recycling of these alloys more effectively. To achieve a complete understanding of the intermetallic morphologies formed in Al-Cu-Fe and Al-Cu-Fe-Ni alloys, phases composing base alloys of the Al-Ni and Al-Cu-Ni systems will also be studied.In this project, directional solidification samples of Al-5%Cu-1.2%Fe and Al-5%Cu-1.2%Fe-1%Ni alloys will be manufactured, as well as slowly cooled furnace samples of Al-6%Ni and Al-5%Cu-1%Ni alloys. The Al-Cu alloys containing Fe and Ni were chosen due to their importance in casting alloys pertaining to the 2xx series, and the Al-Ni and Al-Cu-Ni alloys to allow for a careful study of the Al3Ni and Al7Cu4Ni phases, which have important application properties. Laser Surface remelted (LSR) samples will also be produced using Al-5%Cu-1.2%Fe and Al-5%Cu-1.2%Fe-1%Ni alloys as substrates to assess the microstructures generated under extremely rapid solidification conditions.The main objectives of this work are as follows: i) manufacturing samples under different solidification conditions, including chilled molds, laser resolidification, and slow furnace solidification; ii) evaluation of intermetallics formed by X-ray microtomography and EBSD of slowly solidified (<0.3°C/s) samples of the four alloys of interest; and iii) microstructural analysis as a function of cooling rate, and determination of tensile properties, hardness and wear resistance.