UNDERSEA TECHNOLOGY 



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Titanium alloy cylinder, hemisphere model. This model was used to study fabri- 

 cation and structural performance of welded titanium hulls. Titanium, having a 

 high specific strength, is undergoing considerable exploratory development as a future 

 material for deep-submergence applications. 



The modification of the 7-2-1 titanium alloy to a 6Al-2Cb-lTa-0.8Mo 

 titanium has resulted in an alloy which is for practical purposes insensitive 

 to stress corrosion but has lower strength. The 6-2-1-0. 8Mo titanium alloy 

 is now being evaluated for the Navy. 



An important part of the titanium program has been the fabrication 

 work carried out at the Naval Applied Science Laboratory, Brooklyn, 

 N. Y. The largest out-of-chamber weldment ever produced in 3 in. thick 

 titanium alloy was produced at this laboratory. 



Alumina (Aluminum Oxide) 



A Umited number of tests have been conducted on 10 in. alumina 

 spheres, weight displacement equivalent to 0.25, fabricated by ceramic 

 technique by an industrial contractor. The results showed high strength 

 and Uttle scatter. However, the spheres exhibited static fatigue behavior; 

 i.e., strength varied with speed of testing. 



