Effect of Chromium-enhanced Diffusivity on Reverted Transformation in Metastable Austenitic Stainless Steels: Theoretical Calculation and Experiment

Abstract

Effects of nucleation sites and diffusivity enhancement of chromium on reverted transformation of AISI 304 stainless steel during annealing process were investigated. Dynamics calculation revealed that the reverted transformation of strain-induced α’-martensite→γ austenite could were closely associated with active nucleation sites and diffusivity enhancement of chromium in nanocrystalline α’-martensite. The experimental data and the results were in accordance with 2-grain austenite/α’-martensite junctions calculated theoretically, which could result from high chromium diffusion rate in nanocrystalline α’-martensite. In addition, low temperature is not conducive to reversed transformation, while high temperature and long annealing time will lead to inhomogeneous grain size distribution.

Keywords

austenitic stainless steel / anneal / diffusion / phase transformation / strain-induced α′-martensite

References

[1] Jeong SW, Kang UG, Choi JY, et al. Comparative Study of Hardening Mechanisms during Aging of a 304 Stainless Steel Containing α’-Martensite[J]. J. Mater. Eng. Perform., 2012, 21: 1 937-1 942.

[2] du Toit M, Steyn HG. Comparing the Formability of AISI 304 and AISI 202 Stainless Steels[J]. J. Mater. Eng. Perform., 2012, 21: 1491-1 495.

[3] Ningshen S, Kamachi MU. Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels[J]. J. Mater. Eng. Perform., 2010, 19: 274-281.

[4] Huang JX, Ye XN, Gu JQ, et al. Enhanced Mechanical Properties of Type AISI301LN Austenitic Stainless Steel Through Advanced Thermo Mechanical Process[J]. Mater. Sci.Eng. A., 2012, 532: 190-195.

[5] Lu L, Shen YF, Chen XH, et al. Ultrahigh Strength and High Electrical Conductivity in Copper[J]. Science, 2004, 304: 422-426.

[6] Rezaee A, Kermanpur A, Najafizadeh A, et al. Production of Nano/Ultrafine Grained AISI 201L Stainless Steel through advanced thermo-mechanical Treatment[J]. Mater. Sci. Eng. A., 2011, 528: 5 025-5029.

[7] Somani MC, Juntunen P, Karjalainen LP, et al. Enhanced Mechanical Properties through Reversion in Metastable Austenitic Stainless Steels[J]. Metall. Mater. Trans. A., 2009, 40: 729-744.

[8] Lee SJ, Park YM, Lee YK. Reverse Transformation Mechanism of Martensite to Austenite in a Metastable Austenitic Alloy[J]. Mater. Sci. Eng. A., 2009, 515: 32-37.

[9] Rajasekhara S, Ferreira PJ. Martensite → Austenite Phase Transformation Kinetics in an Ultrafine-grained Metastable Austenitic Stainless Steel[J]. Acta. Mater., 2011, 59: 738-748.

[10] Mordyuk BN, Prokopenko GI, Vasylyev MA, et al. Effect of Structure Evolution Induced by Ultrasonic Peening on the Corrosion Behavior of AISI-321 Stainless Steel[J]. Mater. Sci. Eng. A., 2007, 45: 253-261.

[11] Di Schino A, Salvatori I, Kenny JM. Effects of Martensite Formation and Austenite Reversion on Grain Refining of AISI 304 Stainless Steel[J]. J. Mater. Sci., 2002, 37: 4 561-4 565.

[12] Forouzan F, Najafizadeh A, Kermanpur A, et al. Production of Nano/Submicron Grained AISI 304L Stainless Steel Through the Martensite Reversion Process[J]. Mater. Sci. Eng. A., 2010, 527: 7 334-7 339.

[13] Clemm PJ, Fisher JC. The Influence of Grain Boundaries on the Nucleation of Secondary PhasesL’influence Des Joints Intercristallins Sur la Germination de Phases SecondairesDer Einfluss Von Korngrenzen Auf Die Keimbildung Sekundärer Phasen[J]. Acta. Mater., 1955, 3: 70-73.

[14] Dinsdale AT. SGTE Data for Pure Elements[J]. Calphad, 1991, 15: 317-425.

[15] Wang ZB, Tao NR, Tong WP, et al. Diffusion of Chromium in Nanocrystalline Iron Produced by Means of Surface Mechanical Attrition Treatment[J]. Acta. Mater., 2003, 51: 4 319-4 329.

[16] Szabo PJ. Effect of Partial Recrystallization on the Grain Size and Grain Boundary Structure of Austenitic Steel[J]. Mater. Charact., 2012, 66: 99-103.

[17] Elizabeth AH, Foiles SM. How Grain Growth Stops: A Mechanism for Grain-Growth Stagnation in Pure[J]. Science, 2010, 328: 1 138-1 141.