Assessment of the solidification behavior and microhardness of Sb-modified Sn-Ag alloys

Author(s)

de Freitas, Pamella Raffaela Dantas ; Sobral, Bruno Silva ; de Sousa, Rai Batista ; Paixao, Jeverton Laureano ; de Carvalho, Zulmara Virginia ; Spinelli, Jose Eduardo ; Silva, Bismarck Luiz

• Document type: Journal article
• Source: MICROELECTRONICS RELIABILITY; v. 167, p. 21-pg., 2025-02-21.

Abstract

The present study aims to analyze the effect of antimony (Sb) additions (0.2 % and 2.0 % in wt.%) on the microstructure solidification parameters (cooling rate and growth rate), temperatures related to phase transformation, macrosegregation and microhardness of the Sn-2.0 wt% Ag alloy. The samples have been characterized using techniques such as Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), X-ray Diffraction (XRD) and Vickers microhardness. Thermodynamic calculations were also performed in order to study the evolution of the solidification and the phase fractions. The microstructures of the Sn-Ag-Sb alloys are completely dendritic with a Sn-rich matrix (beta-Sn) surrounded by a eutectic mixture, beta-Sn + Ag3Sn. The additions of Sb promoted a slight microstructural refinement and a slight increase in liquidus and solidus temperatures, when compared to the binary alloy. Ag3Sn intermetallics showed fibrous and spherical morphologies, with spherical dominating at cooling rate (T) over dot(L) > 5.1 degrees C/s and (T) over dot(L) > 2.9 degrees C/s for 0.2 wt.% Sb and 2.0 wt.% Sb, respectively. The Sb increased Vickers microhardness, particularly in the Sn-Ag-2wt.%Sb alloy due to solid-solution and dendritic refinement strengthening. (AU)

• FAPESP's process: 23/06107-3 - Study of the growth of AlFe primary phases in Al alloys and of intermetallic layers in Sn-Bi-X/copper joints
• Grantee: José Eduardo Spinelli
• Support Opportunities: Regular Research Grants