Low temperature tensile deformation and acoustic emission signal characteristics of AISI 304LN stainless steel

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 597; pp. 37 - 45
• Main Authors: Barat, K., Bar, H.N., Mandal, D., Roy, H., Sivaprasad, S., Tarafder, S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 12-03-2014; Elsevier
• Subjects: Acoustic emission; AISI 304LN stainless steel; Applied sciences; Austenitic stainless steels; Counting; Cross-disciplinary physics: materials science; rheology; Cumulative counts; Deformation induced martensite; Ductility; Elasticity. Plasticity; Exact sciences and technology; Low temperature tensile; Martensite; Martensitic transformations; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Piece-wise logarithmic fit; Stainless steels; Strength; Tensile deformation; Acoustic emission; Cumulative counts; Deformation induced martensite; Low temperature tensile; Piece-wise logarithmic fit; AISI 304LN stainless steel; Acoustic emission testing; Temperature dependence; Scanning electron microscopy; Deformation; Ductility; Temperature effect; Crystal defect; Tension test; Tensile stress; Stainless steel; Morphology; Martensitic transformation; Void; Non linear effect; Microstructure; Fractography; Martensite
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2013.12.067

This investigation examines low temperature tensile deformation behavior of AISI 304LN stainless steel along with synergistic analysis of acoustic emission signals. The tensile tests are done at a range of temperatures starting from 283K till 223K. The fracture surfaces of the broken specimens are investigated using scanning electron microscope. The amount of deformation induced martensite is measured using a feritscope. The obtained results reveal that with decrease in test temperature, both strength and ductility increase. The increase in strength and ductility with decreasing temperature is explained in terms of void morphologies and formation of deformation induced martensite. The rapid increment in strength and ductility at 223K is associated with the burst of martensitic transformation at that temperature; which has been clarified from acoustic emission signals. An additional initiative has been taken to model the evolution of martensite formation from the observed cumulative emission counts using a non linear logarithmic functional form. The fitted curves from the recorded acoustic emission cumulative count data are found to be better correlated compared to earlier obtained results. However, at 223K normal non-linear logarithmic fit is not found suitable due to presence of burst type signals at intervals, therefore; piecewise logarithmic function to model acoustic emission bursts is proposed.