Interstitial content

Further increased sensitivity and accuracy of electronic tools will enable non-destructive evaluation of many metallurgical properties, including composition, interstitial content, residual strain, and many other important variables. A combination of multiple tools will allow for more precise measurement, without the need of testing standards... 

For a material to be soft magnetically, its domain walls must move easily. The principal obstacles to domain wall movement are inclusions and grain boundaries. Low dislocation contents, residual stresses, and a low interstitial content, are also important. 

Ti-6A1-4V is an alpha-beta alloy that can be modified extensively by both thermal and thermomechanical processing to produce a large variety of microstructures and hence a wide spectrum of mechanical properties. The beta-transus temperature is approximately 1000 °C (1830 °F) and is a function of interstitial content (Ref 1). Samples of Ti-6A1-4V cooled at relatively slow rates from elevated temperatures contain mainly the alpha and beta phases as a result of diffusional transformations, while those cooled rapidly may also contain martensitic phases such as the cc (hep structure) or the a" (orthorhombic structure) phases. 

The a -f- p Alloy Ti-6A1-4V The ductility of annealed Ti-6A1-4V is fairly independent of temperature between room temperatiire and 77 K. Below 77 K, it decreases rapidly as the temperature continues to fall toward 20 K. The ductility of the annealed alloy is twice as great as that of the solution-treated-and-aged material—e.g., Sb77k = 11.4% as compared with 4.9% (at normal interstitial levels). Reducing the interstitial content influences the tensile properties only marginally but improves the fi acture toughness by 130% at room temperature, and by 40% at20K... 

Con70] Conrad, H. and Jones, R, Effects of Interstitial Content and Grain Size on the Mechanical Behavior of Alpha Titanium Below 0.4 Tm, in [Jaf70], p. 489-501... 

O, 0.20 Fe, 0.03 N, and 0.10 C wt.% max. Equivalent compositions fi om other specifications are best determined by mechanical properties, because small variations in interstitial contents may raise yield strengths above maximum permitted... 

Nl = normal Interstitial content ELI = extra-low interstitial content. Source R.L. Robler and R.P. Reed, in Advances in Cryogenic Err-aneering, Vol 24, K.D. Trmnneihaus etal., Ed-, Plenunt Press, 1978, p 82-90... 

Beta Transus. Approximately 1040 °C (1900 °F) with normal interstitial contents... 

Ultrahigh purity the (C -l- N) interstitial content is less than 150 ppm... 

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