Corrosion-fatigue properties of plasma-based low-energy nitrogen ion implanted AISI 304 L austenitic stainless steel in borate buffer solution

SURFACE & COATINGS TECHNOLOGY

卷:288

Article

Wang, K. S.¹  Che, H. L.¹  Lei, M. K.¹ 

[1] Dalian Univ Technol, Sch Mat Sci & Engn, Surface Engn Lab, Dalian 116024, Peoples R China

关键词: Plasma-based low-energy ion implantation;    High-nitrogen face-centered-cubic phase;    Corrosion-fatigue;    Austenitic stainless steel;    Borate buffer solution;   

DOI  :  10.1016/j.surfcoat.2016.01.010

来源: Elsevier

【 摘 要 】

AISI 304 L austenitic stainless steel was modified by using the plasma-based low-energy nitrogen ion implantation (PBLEII) at a process temperature of 400 degrees C for a processing time of 4 h in order to improve the corrosion-fatigue resistance of the austenitic stainless steel. A single high-nitrogen face-centered-cubic phase (gamma(N)) layer with a maximal nitrogen concentration of about 25 at.% was formed on the nitrogen-modified austenitic stainless steel. Compared with the original austenitic stainless steel, the gamma(N) phase layer on the austenitic stainless steel possessed a significant improvement in corrosion resistance in the borate buffer solution with a pH value of 8.4. The corrosion-fatigue properties of the gamma(N) phase layer on the austenitic stainless steel were examined by the push-pull fatigue experiments with a ratio R of tensile and compression of -1 in the borate buffer solution. The gamma(N) phase layer has an increased corrosion-fatigue strength up to 230 MPa from 180 MPa of the original austenitic stainless steel with an apparent increase of about 28%. The corrosion-fatigue crack initiation in the gamma(N) phase layer was found as a controllable stage in the fracture process at the interface between the gamma(N) phase layer and the austenitic stainless steel matrix with the arc corrosion-fatigue source. Some tiny corrosion-fatigue striations were obtained on the corrosion-fracture surfaces of the gamma(N) phase layer. The high density of slip bands and dislocations in the gamma(N) phase layer was able to prevent the crack initiation and propagation, leading to improvement of the corrosion fatigue properties in the borate buffer solution. (C) 2016 Elsevier B.V. All rights reserved.

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