Mechanical Properties of Doped Solder SAC-Q for High Strain Rate Testing at Extreme Surrounding Temperatures for 6 Months of Isothermal Aging

Abstract

Abstract In various industries, including automobile industry, oil and gas, aerospace, and medical technology, electronic components are subjected to significant strain during shocks, vibrations, and drop conditions. Electronic components of this type are frequently subjected to extreme temperatures ranging from –65 °C to 200 °C. These electronic equipment are frequently subjected to strain rates of 1 to 100 sec−1 in sensitive conditions. SAC-Q, SAC-R, Innolot, and other doped SAC solder alloys have recently been introduced to electronic components and packages. SAC-Q refers to the addition of Bi to the Sn-Ag-Cu composition. The mechanical characteristic results and statistics for lead-free solder alloys are particularly important for increasing electronic package stability and high-temperature storage and strain rates. Furthermore, the mechanical characteristics of solder alloys can be dramatically altered owing to thermal aging, which causes microstructure alteration. For high-temperature aging for longer durations and testing at extremely low to very high working temperatures, SAC-Q solder alloy data is not available. The SAC-Q solder material was tested and studied at working temperatures ranging from −65 °C to 200 °C, with strain rates of up to 75 sec−1, for this study. A comparison was also done with the SAC305 solder, which had been thermally aged and tested under identical conditions. Isothermal aging specimens were kept at 100 °C for up to 180 days following manufacturing and reflowing when tensile studies were conducted at various operating temperatures. This study develops and describes stress–strain curves for a wide variety of strain rates and test temperatures. In addition, the test results and data collected were matched to the Anand viscoplasticity model, and Anand constants were calculated by estimating high strain rate behavior throughout a wide range of operating temperatures and stress levels. In addition, for BGA package assembly with PCB, FE analysis was performed for drop/shock events. For varied aging circumstances of SAC-Q solder ball joints, hysteresis stress–strain curves and plastic work density curves are generated.