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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The effect of the chemical distribution on the mechanical properties of the Al-5.5wt%Si-5wt%Zn-0.2wt%Mg alloy after thixoforging and solution heat treatment

Full text
Author(s):
Gabriela Lujan Brollo [1] ; Cecília Tereza Weishaupt Proni [2] ; Eugênio José Zoqui [3]
Total Authors: 3
Affiliation:
[1] Unicamp. Departamento de Engenharia de Manufatura e Materiais - Brasil
[2] Unicamp. Departamento de Engenharia de Manufatura e Materiais - Brasil
[3] Unicamp. Departamento de Engenharia de Manufatura e Materiais - Brasil
Total Affiliations: 3
Document type: Journal article
Source: MATERIA-RIO DE JANEIRO; v. 27, n. 2 2023-01-13.
Abstract

ABSTRACT The effect of heat and strain during the semisolid processing route on the microstructural evolution and mechanical performance of the Al-5.5wt%Si-5wt%Zn-0.2wt%Mg alloy was evaluated. The as cast alloy was heated and partially melted to 588 °C (fs = 0.40), thixoformed (in an open die forged) and solution heat-treated (SHT) at 525 °C for 1 to 6 h. The microstructural evolution and chemical distribution (SEM-EDS) of the main alloying elements were evaluated at each step of the processing route. The SHT for 2.5 h after thixoforming showed to be adequate considering (a) the spheroidization of Si crystals, (b) the formation of Fe- and Mn-rich platelet-like particles in the eutectic phase, (c) the Mg dissolution from the Mg2Si conglomerates and (d) the homogeneous Zn diffusion along the entire part. As a consequence of the higher circularity of secondary particles, the possibility of crack formation and propagation under stress was minimized. The possible formation of solute clusters and GP zones containing Zn, Mg, Si and Cu was enabled due to the dissolution and diffusion of secondary elements during SHT, which increased the alloy’s mechanical strength. Larger Si crystals and the homogeneous spatial spread of Zn resulted in the hardness increase of the SHT alloy. (AU)

FAPESP's process: 15/22143-3 - Fatigue behaviour of thixoformed alloys
Grantee:Eugênio José Zoqui
Support Opportunities: Regular Research Grants
FAPESP's process: 09/08478-1 - Continuous Casting and Thixoforming of new Al-Si-Cu-Mg alloys
Grantee:Luis Vanderlei Torres
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 13/09961-3 - Upgrade of the Foundry and Thixoforming Laboratory at FEM/Unicamp
Grantee:Eugênio José Zoqui
Support Opportunities: Regular Research Grants