Cooling Rate and Fibrous Type Striated Deformations Effects on the Mechanical Properties of Sn 8.6 wt. % Zn Alloy

F. Abd El-Salam, H.Y. Zahran , Shereen. M. Abdelaziz

Sn-Zn alloy has been taken as one of the most important lead free solder alloys due to the toxicity and the alpha radiation of lead impurities. The influence of cooling rate on the mechanical and structural properties of Sn – 8.6 wt. % Zn lead free solder alloy was studied.  The microstructure of the quenched and slowly cooled samples of Sn – Zn alloy was examined by X – rays analysis and Scanning electron microscopy (SEM). There is an appearance of fibrous type striated deformations on the surfaces of the quenched samples more than those on the surfaces of the slowly cooled samples. The hardening parameters were obtained through stress-strain relations in the temperature range 333-393K for slowly cooled and quenched samples. The quenching samples indicated an improvement in the mechanical properties. The energy activated the rate controlling mechanisms has been calculated and found to be 17.85 and 24.57 kJ/mol for slowly cooled and quenched samples respectively. These values were found to be close to those reported for the grain boundary sliding mechanism in Sn-based alloys.