Effect of aging treatment on microstructure and creep behaviour of Sn–Ag and Sn–Ag–Bi solder alloys

Abstract

The present study was undertaken to investigate the influence of aging temperature on the creep behaviour of Sn–Ag and Sn–Ag–Bi solder alloys at testing temperatures ranging from 333 to 363 K under constant stress of 7·80 MPa. The steady state creep rate was found to increase continuously with increasing aging temperature at all testing temperatures. Results show that addition of Bi to the binary Sn–Ag solder alloy led to a significant increase in the strength and improvement in the creep resistance. The activation energy for the creep process of Sn–Ag and Sn–Ag–Bi solder alloys was found to have an average value of 36 and 45 kJ mol−1 respectively. This might be characterised by diffusion of Ag in Sn. The microstructure of the aged samples for both alloys examined by X-ray diffraction measurements supported the improvement in the creep resistance for Sn–Ag alloy by adding a small trace of Bi.

Effect of Bi Content on the Microstructure and Mechanical Performance of Sn-1Ag-0.5Cu Solder Alloy

“…Creep is typically associated with time-dependent plastic deformation of materials at an elevated temperature under constant uniaxial stress [25]. Most metals and alloys display normal creep curves at temperatures above about 0.5 T m , where T m is the absolute melting point [26]. Typical creep curves include three parts that appear after the initial instantaneous strain (ε o ) upon loading.…”

Microstructure and reliability of Mo nanoparticle reinforced Sn–58Bi-based lead-free solder joints

“…The miniaturisation requirement of the solder interconnect is enhanced by various applications with the rapid development of electronic packaging industry, and it is reported that the average size of the solder ball will be reduced to 10 µm by 2020 [1][2][3][4]. As a new alternative to Sn-Pb solder, Sn-58Bi lead-free solder is successfully applied in the electronics packaging industry due to the advantages of low melting point (139°C), favourable wettability and popular prices [5,6].…”