Shankar, P and Palanichamy, P and Jayakumar, T and Raj, Baldev and Ranganathan, S (2001) Nitrogen redistribution, microstructure, and elastic constant evaluation using ultrasonics in aged 316LN stainless steels. In: Metallurgical and Materials Transactions A, 32 (12). pp. 2959-2968.Full text not available from this repository. (Request a copy)
The presence of even dilute concentrations of nitrogen (0.08 mass pet) is found to have a strong influence on the microstructure of a nuclear grade 316LN austenitic stainless steel, thermally aged at 1123 K.High-resolution transmission electron microscopy (TEM) evidence of pre-precipitation reactions involving formation of Cr-N rich clusters prior to $Cr_2N$ precipitation has been presented. A tendency for cellular precipitation has been observed on continued aging above 500 hours.Beyond 1000 hours, chi precipitates are the most frequently seen phase.The observed microstructural variations correlate well with ultrasonic velocity and attenuation measurements. The present study reveals that nitrogen in solid solution decreases all the elastic constants, namely longitudinal modulus, elastic modulus, shear modulus, and bulk modulus in this steel but has a negligible effect on Poisson's ratio. The stages associated with the precipitation of intragranular coherent $Cr_2N$ are, however, associated with an increase in all the elastic constants including Poisson's ratio.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Springer.|
|Department/Centre:||Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)|
|Date Deposited:||18 Aug 2008|
|Last Modified:||27 Aug 2008 13:43|
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