Abstract
The microstructure and mechanical properties of Sn-3.5Ag-0.5Cu (SAC355) solder alloy reinforced with different amounts of graphitic carbon nitride nanosheets (GCNNs) are assessed. The as-synthesized GCNNs were examined by a scanning electron microscope and X-ray diffraction techniques. A set of composite solders were fabricated by adding GCNNs with different concentrations (0 wt.%, 0.25 wt.%, 0.5 wt.%, and 1.0 wt.%) to SAC355 solder alloy. After a solution heat treatment, samples were immediately aged at temperatures ranging from 343 K to 403 K for 2 h followed by water quenching at 273 K. The mechanical properties of the composite solders were assessed using the indentation hardness test. The experimental results showed that the minimum creep rate values estimated from hardness data increased progressively with increasing weight percentage of GCNNs and/or aging temperature. The homogeneous distribution of GCNNs in the composite solders allows microscopic defects such as cracks to develop throughout the solders leading to higher creep rate values. The calculated values of the stress exponent and the activation energy for the creep process indicated that the creep rate controlling process depends on dislocation core diffusion in the tin matrix.