Microstructure and Mechanical Properties of High-Nitrogen Austenitic Stainless Steels Subjected to Equal-Channel Angular Pressing

The tribocorrosion behavior of 304 stainless steel was studied through comparing the damage behavior of 304 stainless steel in dilute sulfuric acid to that in distilled water by a reciprocating tribotester. The re-passivation behavior, the surface and sectional morphological features, as well as the change of microhardness of samples were studied, and the tribocorrosion mechanism was also discussed. The experimental results reveal that the damage of stainless steel in dilute sulfuric acid was caused by the steel's mechanical removal and electrochemical dissolution. The wear mechanism of stainless steel is abrasive wear, which mainly consists of micro-cutting and peeling. The synergetic action between corrosion and wear is notable. The corrosive environment leads to the embrittlement of the surface layer, and the wear destroys the passivation film and causes galvanic corrosion.

Section: Resultsmentioning

confidence: 99%

Tribocorrosion Behavior of 304 Stainless Steel in 0.5 mol/L Sulfuric Acid

Liu

Duan

Jiang

et al. 2018

“…8. The fracture surface consists of a fiber area and shear lip, and a more pronounced necking phenomenon appears, but they show distinct fracture features [19]. As displayed in Fig.…”

Section: Mechanical Propertiesmentioning

confidence: 96%

Influence of Island Scanning Strategy on Microstructures and Mechanical Properties of Direct Laser-Deposited Ti–6Al–4V Structures

Wang

Shen

et al. 2018

To investigate the influence of island scanning on the microstructures and mechanical properties of direct laser-deposited Ti-6Al-4V structures, two samples are prepared using island scanning and orthogonal successive scanning, respectively. The microstructures, relative density, and mechanical properties of the samples prepared using these two scanning strategies are compared. Each sample exhibits columnar β-grain morphology and basket-weave microstructure characterization. The grains of the sample prepared using island scanning are significantly finer than that prepared by orthogonal successive scanning due to faster cooling during deposition. However, the relative density of the sample prepared using island scanning was slightly smaller due to the concentration of lack-of-fusion pores at the overlap zone of the island. Tensile testing at room temperature indicates that the ultimate tensile strength and yield strength of the sample prepared using island scanning is enhanced due to finer grains, while the ductility of the sample is weakened due to defects.

“…Nowadays, stainless steels are still widely used for clinical applications. With outstanding comprehensive performance, high-nitrogen nickel-free stainless steel (HNS) has broad application prospects as a new biomedical metal material [4][5][6][7][8][9]. In HNS, nitrogen (N) is used to replace nickel (Ni) to stabilize austenite structure, which can effectively avoid the sensibilization and teratogenesis effects of Ni on human body [2,3].…”

Section: Introductionmentioning

confidence: 99%

Enhancing General Corrosion Resistance of Biomedical High Nitrogen Nickel-Free Stainless Steel by Nitric Acid Passivation

Yang

Wang

et al. 2019

Self Cite

A systematic study of nitric acid passivation was investigated to enhance the general corrosion resistance of biomedical high-nitrogen nickel-free stainless steels (HNSs). After passivation, the corrosion rate of HNS could dramatically reduce to 1/20 of the untreated in 37 °C 0.9 wt% NaCl solutions. Then, the passive film on HNS was analyzed by X-ray photoelectron spectroscopy. It was found that chromium enrichment in the passive film and nitrogen enrichment in the film/metal interface contributed to the improvement in general corrosion resistance of HNS.