Surface functionalization of AA2017 powder for additive manufacturing

• Grant number: 20/09544-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): February 01, 2021
• Status: Discontinued
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Piter Gargarella
• Grantee: Bruna Fernanda Batistão
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 17/27031-4 - Effect of process parameters on the metallurgical characteristics of additive-manufactured alloys, AP.JP
• Associated scholarship(s): 22/02760-1 - Surface functionalization of the AA2017 aluminum alloy powder for use in additive manufacturing, BE.EP.DR

Abstract

Additive Manufacturing (AM) processes allow the manufacture of almost totally dense parts with complex geometry, material savings, and a minimal need for further processing. Among AM techniques, Selective Laser Melting (SLM) stands out for the manufacture of metallic materials, and the main aluminum alloys used in SLM are the AlSi10Mg and Al12Si alloys due to the presence of silicon that improves the flowability of the powder and minimizes volumetric contraction. Unlike the AlSiMg alloys, the high-strength alloys of the 2xxx series present alloys elements that can form complex phases during heat treatment, improving the mechanical properties of these alloys, in addition to the higher ductility, high specific mechanical strength, and good fatigue and corrosion resistance. Among the alloys in this series, the AA2017 is the best known and oldest, however, its application in AM is defaulted due to its extensive solidification interval, which generates the growth of cellular or dendritic grains during solidification, consequently providing the appearance of cracks or porosities after the solidification that compromises the mechanical properties of the final piece. In this sense, the increase in the surface roughness of the AA powder, a procedure called surface functionalization of the powder, would allow greater incorporation of energy during the AM, consequently reducing the porosity and increasing densification of the piece and the velocity of the process, and would also make it possible to obtain a microstructure with fine and equiaxial grains through the addition of particles to the AA powder, which act as heterogeneous nucleation sites during solidification, thereby solving the problems related to the solidification of the AA2017 and enabling its application in AM and the improvement of the mechanical properties of the final piece. Based on this, the present project aims to study the influence of the surface functionalization of the AA2017 aluminum alloy powder in AM through surface treatments of the powder with chemical etching with acidic HCl and basic NaOH solutions, and with deposition of TiC particles on the aluminum alloy powder. The functionalized powders and powders without surface treatments will be characterized, as well as samples produced by SLM using these powders, through microstructural, chemical, and mechanical analysis, in order to understand the influence of the surface functionalization of the powder on the solidification dynamics and final properties of the powder and samples produced. (AU)