A study of microstructural development, hardness and micro-creep of Sn-3.5Ag-0.7Cu lead-free solder alloy prepared by rapid solidification

作者：Gouda El Said^*

来源：European Physical Journal Plus, 2011, 126(9): 84.

DOI：10.1140/epjp/i2011-11084-x

The Sn-3.5Ag-0.7Cu lead-free solder alloy has been prepared by normal casting and melt-spinning techniques to investigate the microstructural development, hardness and micro-creep of this alloy due to rapid solidification. The microstructure of the rapidly solidified ribbons and ingot samples has been investigated by SEM and X-ray diffraction (XRD) techniques. The results showed that the structure of the alloy prepared by normal casting is composed of Cu-Sn and Ag-Sn IMCs finely dispersed in Sn matrix, while these fine dispersions are not present in the rapidly solidified sample indicating that the rapid solidification rate is high enough to retain most of the Ag and Cu elements in nonequilibrium supersaturated solid solutions of beta-Sn. Additionally, the mechanical properties of both slowly and rapidly cooled samples are examined by using Vickers microhardness tester at different loads in the range of them 0.098 to 4.9 N. The hardness value of the rapidly cooled sample was found to be 1.3 times higher than that of the slowly cooled sample due to refinement of the rapidly cooled sample as well as the nonequilibrium solid solutions of Ag and Cu in the beta-Sn matrix. Besides, indentation creep behavior of both slowly and rapidly cooled samples is examined by using Vickers microhardness tester for three different values of the applied loads.

• 出版日期2011-9