Microstructure and dry sliding wear performance of oxide dispersion strengthened austenitic stainless steel

Abstract: The oxide dispersion strengthening (ODS) material are candidates for structural materials in nuclear reactors due to high density of small oxide particles dispersed in the matrix. In this study, the microstructure and wear performance of ZrO₂ stabilized with Y₂O₃ reinforced AISI 316L austenitic stainless steels was investigated. The ODS-316L steel powders were sintered using spark plasma sintering technique. The surface structure and composition of the sintered samples were examined by field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The experimental results were compared with the untreated 316L material. Tribological tests were performed on a ball-on-disc wear tester under dry condition at different applied loads from 5 to 35 N. The sliding distance was 2 mm for 1000 s. A tungsten carbide (WC) ball was used as a counterface material. Results showed that addition of ZrO₂ significantly improved the microhardness values while the presence of ZrO2 phase in the 316L matrix reduces the friction coefficient and increased resistance to sliding wear

Effect of build direction on the microhardness and dry sliding wear behaviour of laser additive manufactured Ti-6Al-4V

Abstract: This work presents micro structural and tribological behaviour of Ti-6Al-4V fabricated by direct metal laser sintering technique. The laser sintering was carried out at laser power of 170 W in an argon atmosphere. The microstructure, phase composition, micro hardness and wear study were determined. It has been found that specimens built vertically (VB) contained vanadium carbide (VC) and titanium oxide (TiO) phases in the present of α and β phases resulting in higher micro hardness as compared to horizontal build (HB) specimens. Wear volume loss was determined in a dry sliding wear configuration. An increase in applied load from 5 N to 25 N resulted in an increment in wear volume loss. The presence of delamination could be observed on the worn surface of HB specimen

Effect of build direction on the microhardness and dry sliding wear behaviour of laser additive manufactured Ti-6Al-4V

Abstract: This work presents micro structural and tribological behaviour of Ti-6Al-4V fabricated by direct metal laser sintering technique. The laser sintering was carried out at laser power of 170 W in an argon atmosphere. The microstructure, phase composition, micro hardness and wear study were determined. It has been found that specimens built vertically (VB) contained vanadium carbide (VC) and titanium oxide (TiO) phases in the present of α and β phases resulting in higher micro hardness as compared to horizontal build (HB) specimens. Wear volume loss was determined in a dry sliding wear configuration. An increase in applied load from 5 N to 25 N resulted in an increment in wear volume loss. The presence of delamination could be observed on the worn surface of HB specimen

Tribocorrosion behaviours of AISI 310 and AISI 316 austenitic stainless steels in 3.5% NaCl solution

Abstract: In this paper the tribocorrosion behaviours of AISI 310 and AISI 316 stainless steels have been studied under reciprocating sliding condition in 3.5% NaCl solution, using a pin-on-disk tribometer integrated with a potentiostat for electrochemical control. Different sliding loads were used at a constant rotational speed of 60 rpm. The results show that sliding load has significant effect on the tribocorrosion behaviour of both materials. Corrosion attack was severe at sliding load conditions in both materials suggesting corrosion-induced wear as the dominant of the two synergistic components. However, at low sliding load, anodic dissolution and pit formation in AISI 316 was accelerated by sliding action causing wear-induced corrosion to be dominant

Influence of SiAlON ceramic reinforcement on Ti6Al4V alloy matrix via spark plasma sintering technique

Abstract : The titanium-based composite was fabricated by strengthening Ti6Al4V alloy with addition of SiAlON ceramics utilizing spark plasma sintering technique. Ti6Al4V and SiAlON powders were mixed in a T2F Turbula mixer with different propor- tions (5, 10, 15 and 20 vol%) and the admixed powders were consolidated using spark plasma sintering to produce titanium matrix composites. The characterization of the sintered composites was performed using X-ray diffraction, optical microscopy and scanning electron microscopy. The influence of SiAlON additions on densification, microstructure, microhardness and fracture morphology were investigated on the sintered composites. The experimental results revealed that the densification of the sintered titanium matrix composites was in the range of 95%–98%, which decreased with an increase in SiAlON addition. However, an increase in microhardness values ranging from 363 to 574 HV0.1 was achieved. The microstructure shows that the SiAlON ceramic particle was uniformly distributed within the titanium matrix composites which comprises of a mixture of lamellar colonies with β grain boundaries. The fracture features of all composites exhibit mixed fracture of both intergranular and transgranular fracture mechanism

Modeling and Simulation of Hydrogen Storage Device for Fuel Cell Plant

The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity, thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative renewable energ

A comparative study of spark plasma sintering and hybrid spark plasma sintering of W-4.9ni-2.1Fe heavy alloy

Abstract: Mixed 93W-4.9Ni-2.1Fe powders were sintered via the spark plasma sintering (SPS) and hybrid spark plasma sintering (HSPS) techniques with 30 mm and 60 mm samples in both conditions. After SPS and HSPS, the 30 mm and 60 mm alloys (except 60mm-SPS) had a relative density (>99.2%) close to the theoretical density. Phase, microstructure and mechanical properties evolution of W-Ni-Fe alloy during SPS and HSPS were studied. The microstructural evolution of the 60 mm alloys varied from the edge of the sample to the core of the sample. Results show that the grain size and the hardness vary considerable from the edge to the core of sintered sample of 60 mm sintered using conventional SPS compared to hybrid SPS. Similarly, the hardness also increased from the edge to the core. The 60 mm-HSPS alloy exhibit improved bending strength than the 60 mm-SPS, 1115 MPa and 920 MPa respectively, former being similar to the 30 mm-SPS and HSPS alloys. The intergranular fracture along the W/W grain boundary is the main fracture modes of W-Ni-Fe, however in the 60 mm-SPS alloy peeling of the grains was also observed which diminished the properties. The mechanical properties of SPS and HSPS 93W-4.9Ni-2.1Fe heavy alloys are dependent on the microstructural parameters such as tungsten grain size and overall homogeneity

Modeling and Simulation of Hydrogen Storage Device for Fuel Cell Plant

The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity, thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative renewable energy

Influence of phase composition and microstructure on corrosion behavior of laser based Ti�Co�Ni ternary coatings on Ti�6Al�4V alloy

Although Tie6Ale4V alloy has wide applications in marine and chemical industries, its application is highly limited in corrosive environment such as sulphuric acid. This is due to the dissolution of the passive titanium hydride (TiH 2) film formed on the surface which accelerates the corrosion of titanium alloy in concentrated sulphuric acid. In this work, laser surface modification technique was used to develop high performance antiecorrosive coatings for aggressive sulphuric environment. The effects of parameter variations and volume fraction of TieCoeNi clad layer on Tie6Ale4V were investigated. The corrosion behaviors of Ti-6A-l4V, TiCoe10Ni and CoNie10Ti coatings were studied in 0.5 M sulphuric acid using potentiodynamic polarization technique. Thereafter, the morphologies of the coatings before and after corrosion were analyzed using scanning electron microscope (SEM) equipped with energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD) analysis to examine phase compositions and changes. The corrosion result shows that the clad compositions have significant influence on the po- tential by shifting the potential to more noble values and reduced the corrosion rate when compared with as-received Tie6Ale4V. In addition, the corrosion resistance performance of CoNie10Ti deposited at 1.2 m/min is best among all the ternary coated samples. The increase in corrosion resistance of alloys with cobalt and nickel on titanium is due to formation of dense passive CoO, TiO, TiAl, Ni 2TiO 3, V 2O 5 and Al 2O 3 oxides on the samples surfaces. With this result, the use of laser cladding technique could be established in improving the corrosion resistance of Tie6Ale4V with TieCoeNi alloy coatings

Microstructure and biocorrosion studies of spark plasma sintered yttria stabilized zirconia reinforced Ti6Al7Nb alloy in Hanks' solution

Funding Information: The authors are grateful to National Research Foundation (NRF), South Africa for financial support under the.Thuthuka Grant number TTK180419322687 UID: 117843 . Publisher Copyright: © 2022 The AuthorsA study of spark plasma sintered Ti6Al7Nb alloy reinforced with yttria stabilized zirconia (YSZ) has been carried out to assess the biocorrosion response in Hank's solution. The results indicate that the microstructural changes resulting from YSZ addition to Ti6Al7Nb were considerably different from pure Ti6Al7Nb. All the Ti6Al7Nb + YSZ composites showed a higher Vickers microhardness value with Ti6Al7Nb + 10%YSZ exhibiting the most enhanced hardness value of 955.3 HV0.1. Furthermore, all Ti6Al7Nb + YSZ present higher corrosion resistance in Hank's solution than Ti6Al7Nb alloy except Ti6Al7Nb + 1YSZ which shows a significant drop in Ecorr and Icorr values. This could be due to grain refinement with less stable oxide film growth kinetics. The combination of mechanical property and corrosion resistance of the fabricated Ti6Al7Nb + YSZ alloy could make it a suitable material for dental implant in the nearest future.Peer reviewe