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

Abstract

In the present study, the Sn-1.7Sb-1.5Ag solder alloy and the same material reinforced with 5 vol.% of 0.3-lm Al 2 O 3 particles were synthesized using the powder metallurgy route of blending, compaction, sintering, and extrusion. The impression creep behavior of both monolithic and composite solders was studied under a constant punching stress in the range of 20 MPa to 110 MPa, at temperatures in the range of 320 K to 430 K. The creep resistance of the composite solder was higher than that of the monolithic alloy at all applied stresses and temperatures, as indicated by their corresponding minimum creep rates. This was attributed to the dispersive distribution of the submicron-sized Al 2 O 3 particles in the composite solder. Assuming a power-law relationship between the impression stress and velocity, average stress exponents of 5.3 to 5.6 and 5.8 to 5.9 were obtained for the monolithic and composite materials, respectively. Analysis of the data showed that, for all loads and temperatures, the activation energy for both materials was almost stress independent, with average values of 44.0 kJ mol À1 and 41.6 kJ mol À1 for the monolithic and composite solders, respectively. These activation energies are close to the value of 46 kJ mol À1 for dislocation climb, assisted by vacancy diffusion through dislocation cores in the Sn. This, together with the stress exponents of about 5 to 5.9, suggests that the operative creep mechanism is dislocation viscous glide controlled by dislocation pipe diffusion.

Effect of silver and indium addition on mechanical properties and indentation creep behavior of rapidly solidified Bi–Sn based lead-free solder alloys

“…The slope of resultant lines according to sergeant-Ashby model is À1/n. The stress exponent values are in the range of 4.3-5.9 depending on the composition of used alloys and that agrees with the previous results (n ¼4.5 [24] and n ¼5.3-5.6 [42]. According to the powerlaw creep, a decrease in stress exponent would result in an increase in creep rate due to a decrease in yield strength [43,44].…”

Influence of Titanium Oxide on Creep Behavior, Microstructure and Physical Properties of Tin-Antimony and Tin-Aluminum-Antimony Based Bearing Alloys

“…The slope of the resultant lines Table 7. These exponent values are in the range of 2.16 to 5.75 depending on the composition of used alloy and that agreed with the pervious results (n= 4.5 [19] and n ~ 5.3 to 5.6 and 5.8 to 5.9 [20]. The change in stress exponent values are attributable to microstructural features (changing in  matrix such as change in the lattice parameters, solid solution, size and distribution of strengthening phases, intermetallic phases) and that is agree with the pervious results [21].…”

Titanium Oxide and their Effects on Structure, Physical Properties and Electrochemical Corrosion Parameters of Alloys

“…x alloys which calculated using Mulheam-Tabor method are given in Table 24. These exponent values are in the range of 2.16 to 3.07 depending on the composition of alloy and that agreed with the pervious results [31,32]. The change in stress exponent values are…”