Room-temperature indentation creep of lead-free Sn-5%Sb solder alloy

Abstract

Creep behavior of the lead-free Sn-5%Sb solder alloy was studied by long-time Vickers indentation testing at room temperature. Four different conditions of the material were examined. These were unhomogenized cast (UC), homogenized cast (HC), unhomogenized wrought (UW), and homogenized wrought (HW) conditions. Based on the steady-state power-law creep relationship, the stress exponents were determined through different methods of analysis, and in all cases, the calculated exponents were in good agreement. The stress exponent values of about 5 and 12, depending on the processing route of the material, are very close to those determined by room-temperature conventional creep testing of the same material reported in the literature. For the HW condition, the n value of about 5 together with a very fine grain size of 4.5 µm and a high volume fraction of second-phase particles of 8.6% may suggest that dislocation climb is the creep mechanism. For all other conditions with different grain sizes and second-phase volume fractions, however, the high n value of 12 implies that the operative creep mechanism is dislocation creep, which is independent of grain size.

Impression Creep of a Lead-Free Sn-1.7Sb-1.5Ag Solder Reinforced by Submicron-Size Al2O3 Particles

“…As mentioned earlier, these intermetallics are the main strengthening agents in the present solder, while Sb has also a solid-solution hardening effect. In the composite solder, however, the material benefits from the extra hardening caused by the submicron-sized Al 2 analysis confirms that the particles are comprised of aluminum and oxygen with some Sn picked up from the matrix. These particles are the main cause of the enhanced creep resistance of the composite solder with respect to the monolithic material.…”

“…1,2 Accordingly, many lead-free Sn-based alloy systems with different alloying elements such as Ag, In, Cu, Zn, Bi, Ni, and Sb have been developed and their microstructures, mechanical properties, and wettability reported. Among the developed lead-free solders, those containing Sb and Ag could be of interest because of their suitable mechanical and creep properties.…”

Preparation, Microstructure and Properties of Environmentally Friendly Sn-58Bi Eutectic Solder Ribbon for Electronic Package

“…So the instantaneous cooling speed is deduced as: (1) (2) According to Equation (2), v increases with decreased y. Therefore, the thickness of ribbon can be reduced by increasing the roller line speed, inducing to increase the instantaneous cooling rate.…”

“…Lead contamination can cause a bad effect on the growth of green plants and the intellectual development of children. Concerns about environmental and health problems caused by the toxicity of lead have resulted in serious restrictions on the use of these Pb-containing solders [2][3][4]. For example, in 2006 European Union restricted the intentional use of Pb in consumer electronics in European Union by the restriction of Hazardous Substances (RoHS) Directive [5].…”

Creep of Sn-9Zn as measured by a bending test method

“…For solder materials, however, efforts have been made in seeking alternative methods to evaluate their creep property, where the reason is economical or technical, rather than scientific. In the past years, impression/indentation creep testing, have been successfully employed to characterize creep behavior of lead-free solder alloys [1][2][3][4][5][6] , which shows the practical needs and appreciation of simpler methods for creep tests.…”