STRESS SYSTEMS IN THK St)LDEHLESS W1{AP1'HD CONNKCTION 1107 



era: 



11- u. 



(To: 

 i-i- 



o< 



Ob 



i=zi 

 <- 



0.6 



I02 



TIME IN SECONDS 



Fig. 12 — • Stripping force curves for aluininum on nickel silver as a function of 

 time for four temperatures. 



strength is obtained and is shown in Fig. 13. The sheai'ing strength thus 

 obtained approaches 6000 psi for long times at high temperatures. This 

 value agrees approximately with the accepted value for bulk aluminum. 

 Calculating the activation energy of diffusion as previously outlined, 

 one obtains the curve for aluminum in Fig. 10. 



The advantage of a diffusion layer such as tin or aluminum as an 

 element in the solderless wrapped connection is shown by the data of 

 Fig. 14 which shows the rate of increase of the stripping force of bare 



^ Ml 



^ <3 



t'^ 2 



go. 1 



< 



10-^ 10'' 10 = 



TIME IN SECONDS 



IQS 



Fig. 13 — Shearing strength of alumiiunn on nickel silver connections as 

 function of time. 



