Microstructure, phase composition and hardness evolution in 316L stainless steel processed by high-pressure torsion

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:657

Article

Gubicza, Jeno¹  El-Tahawy, Moustafa¹  Huang, Yi²  Choi, Hyelim³  Choe, Heeman³  Labar, Janos L.⁴  Langdon, Terence G.² 

[1] Eotvos Lorand Univ, Dept Mat Phys, POB 32, H-1518 Budapest, Hungary

[2] Univ Southampton, Fac Engn & Environm, Mat Res Grp, Southampton SO17 1BJ, Hants, England

[3] Kookmin Univ, Sch Adv Mat Engn, 77 Jeongneung Ro, Seoul 136702, South Korea

[4] Hungarian Acad Sci, Energy Res Ctr, Inst Tech Phys & Mat Sci, Budapest, Hungary

关键词: Grain refinement;    Hardness;    Nanostructured materials;    Phase transformation;    Steel;   

DOI  :  10.1016/j.msea.2016.01.057

来源: Elsevier

【 摘 要 】

A 316L stainless steel was processed by high-pressure torsion (HPT) to evaluate the grain refinement and phase transformation. The initial material was essentially a single phase gamma-austenite with a coarse grained microstructure of similar to 42 mu m but the grain size was reduced to similar to 45 nm after 10 turns of HPT. In addition, there was a phase transformation and the initial gamma-austenite transformed initially to epsilon-martensite and finally to alpha'-martensite with increasing strain. The dislocation density increased to an exceptionally high value, of the order of similar to 10(16) m(-2), in the main alpha'-martensite phase after 10 HPT revolutions. The formation of the multiphase nanocrystalline microstructure yielded a four-fold increase in hardness to reach an ultimate value of similar to 6000 MPa. The Hall-Petch behaviour of the HPT-processed alloy is compared directly with coarse-grained materials. (C) 2016 Elsevier B.V. All rights reserved.

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