Study on Hardness and Shear Strength with Microstructure Properties of Sn52Bi/Cu + 1% Al2O3 Nanoparticles

Abstract

Abstract The Sn-58Bi (SB) lead-free solder was added with 1% nanoparticles (NP) of aluminium oxide (Al2O3) to investigate the shear strength based on microstructure and joint properties. The microstructures of the SB added with 1% Al2O3 NP containing Bi precipitation and β-Sn grains. The spacing between the lamellar structures of a SB solder alloy was narrower. Proper arrangement of the microstructure of β-Sn, Bi and with the presence of Al2O3 as discrete particles (dispersion strengthening) contributes to the increase on the shear strength and hardness value. The shear strength of the SB added with 1% Al2O3 NP solder joint was enhanced by 50% compared to the bare SB solder joint while there was a 33% increase in the microhardness as well. The shear test was conducted based on ASTM D1002 specification of single lap joint method. The presence of Al2O3 NP along the interface (Hall-Petch effect) contributes to the improvement in the shear strength by reducing the thickness of the IMC layer and retarding the growth of the Cu6Sn5 IMC layer. This study provides evident results for the enhancement of the mechanical properties of the 1% Al2O3 NP added SB solder.