Tensile properties dependency on crystal size and direction of single crystal Ag3Sn intermetallic compound: a molecular dynamics study

Abstract

The necessities of lead-free solder alloys have been expanded by the advent of eco-friendly technologies of microelectronic packaging industry. Mostly lead-free solder alloys are SAC, which is the alloy of tin, silver and copper metal. Ag3Sn, Cu3Sn and Cu6Sn5 inter-metallic compounds are formed during microelectronic packaging, which reduce the properties of SAC solder joints adversely. The present study explores direction dependent tensile properties of various sized single crystal anisotropic Ag3Sn. Molecular dynamics simulation platform LAMMPS is used to examine the elastic behavior of these crystals by modified embedded atom method (MEAM) potential parameters. The atomistic investigation is performed for four crystal sizes of 30×30×30, 60×60×60, 90×90×90 and 120×120×120 Å3 at a temperature of 298 K and a strain rate of 1010 s−1. A comprehensive insight from this work is that the tensile properties fluctuations due to direction are within 13–25% at any distinct crystal size, whereas fluctuations at any specific direction are within 5–17% for mentioned interest of crystal sizes. An optimum crystal size of 60×60×60 Å3, exhibits maximum tensile properties. However, the fracture initiation patterns are quite similar for all sizes and directions where the natures are investigated as ductile.

Keywords

• Mechanical properties
• Intermetallic compounds
• SAC Solder and Anisotropic Ag3Sn