Vacuum Hot Pressing of Oxide Dispersion Strengthened Ferritic Stainless Steels: Effect of Al Addition on the Microstructure and Properties

Ganesan, Dharmalingam; Sellamuthu, Prabhukumar; Prashanth, Konda Gokuldoss

doi:10.3390/jmmp4030093

Cited by 7 publications

(2 citation statements)

References 43 publications

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“…The hardness obtained through the powder metallurgy process was higher when compared to the hardness obtained through other processing techniques. The increase in hardness is due to the higher sintering temperature during the vacuum hot pressing technique [34]. Moreover, it can be seen that the presence of nano crystalline structures led to the formation of a fine-grained metal matrix which was evident from the microstructural analysis from Figure 9b which resulted in superior hardness for the alternate valve steel material developed using the powder metallurgy route.…”

Section: Hardness Measurementmentioning

confidence: 95%

Characterization of Microstructure and High Temperature Compressive Strength of Austenitic Stainless Steel (21-4N) through Powder Metallurgy Route

et al. 2022

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Exposure of the engine valve to high temperatures led to the degradation of the valve material due to microstructural instability and deteriorating mechanical properties. Performance enhancement and alteration in microstructures can be attained through the powder metallurgy route which is a viable method to produce near net shape components. In this current study, the development of austenitic stainless steel (21-4N) through the powder metallurgy route as an alternate material for engine valves was investigated. Mechanical alloying was carried out for the pre-alloyed mixtures and consolidated using vacuum hot pressing. Sintering parameters were fixed at 1200 °C, 50 MPa and at a vacuum level of 10-3 Torr. A scanning electron microscope was used to analyze the morphology of the milled powders. Densities for the hot pressed powders were compared with theoretical densities and found to be around 98–99%. Observations regarding grain size, the presence of austenitic grain, heterogeneous distribution of metal carbides and analysis of chemical composition along the metal matrix were determined using both optical and electron microscopes. X-ray diffraction was carried out for both the consolidated and powder samples. The hot pressed samples exhibited a hardness value of 410 ± 10 Hv. An isothermal compression test for the sintered samples was carried out at a temperature of 650 °C and strain rate of 0.001 s−1. It is showed that the compressive strength of 1380 MPa. An analysis between the room temperature yield strength obtained from hardness measurement and the strengthening mechanism based on the microstructure was conducted. Grain size, dislocation and solid solution are the major strengthening mechanisms which strengthen the material. Overall, the development of valve steel material through the powder metallurgy route exhibited improved metallurgical and mechanical properties in comparison to the corresponding cast product.

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Section: Hardness Measurementmentioning

confidence: 95%

Characterization of Microstructure and High Temperature Compressive Strength of Austenitic Stainless Steel (21-4N) through Powder Metallurgy Route

et al. 2022

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“…The distribution of dispersoids is usually heterogeneous within the metal matrix when ODS alloys are produced through casting processes [9]. Several researchers have investigated the presence of ODS in iron-chromium-nickel alloys which are the promising material for hightemperature applications [10][11][12][13][14][15][16]. The presence of dispersoids like ODS prevents the movement of dislocations at high temperatures which improve the hightemperature properties and creep resistance [17].…”

Section: Oxide Dispersion Strengtheningmentioning

confidence: 99%

Characterisation and structural transformation of yttria dispersed austenitic steel through VHP

Prasad

Pavithra

Dharmalingam

et al. 2021

Materials Science and Technology

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Two different alloys were developed from the mixtures of pre-alloyed powders consisting of ferroalloys to get the required composition of austenitic stainless steel via the powder metallurgy technique along with the presence and absence of Y2O3. The subsequent mechanical alloyed powders were subject to vacuum hot pressing at 1200°C. The samples were subject to microstructural characterisation post-vacuum hot pressing process. With the addition of yttria, the structure of the grains was fine for the mechanical alloyed vacuum hot pressed samples. The TEM analysis revealed the presence of heterogeneous distribution of yttria particles along the grain boundaries. With the addition of yttria within the metal matrix, the hot pressed density was increased marginally.

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Microstructural Evolution and Mechanical Properties of Nano-Yttria Dispersed 316 L Austenitic Stainless Steel by Mechanical Alloying and Sintering

Roy

Shivam

Chattopadhyay

et al. 2021

Trans Indian Inst Met

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Vacuum Hot Pressing of Oxide Dispersion Strengthened Ferritic Stainless Steels: Effect of Al Addition on the Microstructure and Properties

Cited by 7 publications

References 43 publications

Characterization of Microstructure and High Temperature Compressive Strength of Austenitic Stainless Steel (21-4N) through Powder Metallurgy Route

Characterization of Microstructure and High Temperature Compressive Strength of Austenitic Stainless Steel (21-4N) through Powder Metallurgy Route

Characterisation and structural transformation of yttria dispersed austenitic steel through VHP

Microstructural Evolution and Mechanical Properties of Nano-Yttria Dispersed 316 L Austenitic Stainless Steel by Mechanical Alloying and Sintering

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