| 2. |
- Hajiannia, I., et al.
(författare)
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Development of Ultrahigh Strength TRIP Steel Containing High Volume Fraction of Martensite and Study of the Microstructure and Tensile Behavior
- 2018
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Ingår i: Transactions of the Indian Institute of Metals. - : Springer. - 0972-2815 .- 0975-1645. ; 71:6, s. 1360-1367
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Tidskriftsartikel (refereegranskat)abstract
- A new transformation induced plasticity (TRIP) steel containing high volume fraction of martensite was produced by austempering heat treatment cycle. Microstructure and tensile properties of this TRIP steel were investigated and compared to those of a dual phase (DP) steel with high martensite volume fraction. Microstructural analysis showed a mixture of ferrite, bainite, retained austenite and about 25–30 vol% of martensite in the TRIP steel. As a result of the strain induced transformation of retained austenite to martensite, the TRIP steel showed a strength elongation balance of 86% higher than that for the DP steel. In comparison to the commercial TRIP780 steel, the current TRIP steel showed a 15% higher ultimate tensile strength value while maintaining the same level of ductility. TRIP steel also had a larger work hardening exponent than DP steel at all strains.
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| 3. |
- Rashtchi, Hamed, et al.
(författare)
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Evaluation of Ni-Mo and Ni-Mo-P Electroplated Coatings on Stainless Steel for PEM Fuel Cells Bipolar Plates
- 2016
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Ingår i: Fuel Cells. - : John Wiley & Sons. - 1615-6846 .- 1615-6854. ; 16:6, s. 784-800
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Tidskriftsartikel (refereegranskat)abstract
- Stainless steel bipolar plates (BPPs) are the preferred choice for proton exchange membrane fuel cells (PEMFCs); however, a surface coating is needed to minimize contact resistance and corrosion. In this paper, Ni–Mo and Ni–Mo–P coatings were electroplated on stainless steel BPPs and investigated by XRD, SEM/EDX, AFM and contact angle measurements. The performance of the BPPs was studied by corrosion and conduction tests and by measuring their interfacial contact resistances (ICRs) ex situ in a PEMFC set-up at varying clamping pressure, applied current and temperature. The results revealed that the applied coatings significantly reduce the ICR and corrosion rate of stainless steel BPP. All the coatings presented stable performance and the coatings electroplated at 100 mA cm−2showed even lower ICR than graphite. The excellent properties of the coatings compared to native oxide film of the bare stainless steel are due to their higher contact angle, crystallinity and roughness, improving hydrophobicity and electrical conductivity. Hence, the electroplated coatings investigated in this study have promising properties for stainless steel BPPs and are potentially good alternatives for the graphite BPP in PEMFC.
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