Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

In this research, the influence of La2O3 addition on the microstructure, phase stability and mechanical properties of 8 mol% yttria stabilized zirconia (8YSZ) was studied. 8YSZ with La2O3 (9, 12 and 15 wt%) ceramics were fabricated by microwave and conventional sintering at 1400 °C/ 20 min and 1400 °C/ 5 h, respectively. Irrespective of the sintering technique, the relative sintered density was found to decrease with increasing amount of La2O3. The grain growth of 8YSZ was enhanced significantly by the addition of La2O3. The XRD results demonstrated that addition of La2O3 up to 15 wt% did not disrupt the cubic 8YSZ phase regardless of sintering technique; additionally evolution of pyrochlore phase, La2Zr2O7 was observed in all sintered specimens. Vickers hardness of 8YSZ ceramic compacts were also found to decrease with increasing amount of La2O3. © 2018 Elsevier Ltd and Techna Group S.r.l.

Department of Manufacturing Engineering

School of Mechanical Engineering

Vellore Campus

VIT Unitversity

World University root node

Ceramics International

Effect of La2O3 addition and sintering mode on the mechanical properties and microstructural evolution on an 8YSZ ceramic alloy

The effect of graphite content and sintering mode on the tribological and electrical properties of copper has been studied by incorporating varying proportions of graphite flakes (0, 8, 15, 25 and 32 vol%) following powder metallurgy route. The sintering of green compacts was accomplished by microwave and conventional processes at 900 °C with a heating rate of 5 °C min-1 and 20 °C min-1, respectively, and holding time being 60 min for both processes. As expected the densification was observed higher in microwave heating than conventional process. Microstructural examination of microwave samples revealed a fine-grained microstructure. Pin-on-Disc wear test exposed excellent self-lubricating nature of these composites. Best coefficient of friction values were observed for microwave sintered composites. Microwave sintered samples exhibited better hardness, coefficient of friction (COF) and electrical conductivity as compared to their conventionally sintered counter parts. Morphologies of polished surfaces were analyzed to predict the wear mechanisms involved. © 2019 IOP Publishing Ltd.

Materials Research Express

An investigation on tribological and electrical behaviour of conventional and microwave processed copper-graphite composites

Structure-property correlations of W-Ni-Fe-Mo heavy alloys consolidated using spark plasma sintering

Abstract: The effect of alloying additions, such as copper, carbon, and molybdenum with carbonyl iron powder, on the densification behavior, microstructural evolution, and mechanical properties of spark plasma sintered (SPS) compacts have been investigated in this work. The sintering temperature, pressure, and time during SPS were 1120°C, 30 MPa, and 5 min, respectively. Fe–2Cu–0.8C–0.6Mo was found to exhibit the highest density, hardness, and also tensile strength among all the compositions attempted. The microstructural examination of fractured surfaces of the sintered samples revealed the evidence of a mixed mode of fracture in all the alloy compositions. © 2018, Pleiades Publishing, Ltd.

Department of Communication Engineering

School of Electronics Engineering

Physics of Metals and Metallography

Microstructural Evolution of Iron Based Alloys Produced by Spark Plasma Sintering Method

Spark plasma sintering provides faster heating that can create fully, or near fully, dense samples without significant grain growth. In this study, pre-alloyed Ti- 6Al-4 V powder compact samples produced through field assisted sintering in a spark plasma sintering machine are compared as a function of consolidation temperature. The effect of sintering temperature on the densification mechanism, microstructural evolution and mechanical properties of spark plasma sintered Ti-6Al-4 V alloy compacts was investigated in detail. The compact, sintered at 1100°C, exhibited near net density, highest hardness and strength as compared to the other compacts processed at a temperature lower than 1100°C. © Carl Hanser Verlag, München.

Materials Testing

Influence of sintering temperature on mechanical properties of spark plasma sintered pre-alloyed Ti-6Al-4 V powder

Austenitic steel 316L and ferritic steel 434L produced by sintering of atomized powders with additions of different volume fractions (0, 4, 8, and 12 vol.%) of titanium carbide particles in microwave and conventional furnaces are studied. The microwave heating results in more intense densification, hardening, higher corrosion resistance, and grain refinement as compared to sintering in the conventional furnace. Steel 316L with 4 vol.% TiC sintered in the microwave furnace exhibits the highest corrosion resistance. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

Metal Science and Heat Treatment

Effect of TiC Addition and Heating Mode on the Electrochemical Response of Powder Metallurgy Processed Corrosion-Resistant Austenitic and Ferritic Steels

In the current research work, a comparative study on densification and microstructural evolution of CeO2 particle reinforced 8 mol % yttria stabilized zirconia (YSZ) sintered ceramics has been carried out. The ceramic compacts were fabricated via microwave and conventional sintering methods. The sintering conditions that were used for microwave and conventional methods are 1400◦C for 20 min and 1400◦C for 5 h, respectively. The sintered samples were characterized for densification, microstructural behavior, and hardness. Microwave sintering method of sintering resulted in high sintered densities as compared to the conventional counter parts. Microwave sintered samples exhibited finer grains as compared to conventionally sintered specimens. The grain size of the 8YSZ+CeO2 sintered ceramics was found to decrease with CeO2 addition. The X-ray diffraction (XRD) results showed no phase change because of CeO2 addition. The Vickers hardness was found to increase with increasing amount of CeO2. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

Fulltext

Metals

Effect of Heating Mode on Sinterability of YSZ+CeO2 Ceramics

Silicon carbide particle reinforced W–Ni–Fe heavy alloys were prepared using conventional and spark plasma sintering techniques. Comparative analysis based on the densification response, microstructural and mechanical properties were done. The powder sintered using SPS technique was found to exhibit, good density and mechanical properties over the conventional sintering. Detailed fractography revealed a mixed mode and intergranular fracture. The reinforcement of SiC in W–Ni–Fe, had significantly increased the hardness and other mechanical properties of the heavy alloy composites. © 2017, The Indian Institute of Metals - IIM.

Transactions of the Indian Institute of Metals

Densification of SiC Particle Reinforced W–Ni–Fe Heavy Alloy Composites Through Conventional and Spark Plasma Sintering

The present study compares the mechanical and electrochemical behaviour of austenitic (AISI 316L) stainless steel compacted at various pressures (200, 400 and 600 MPa) and conventionally sintered at super-solidus temperature of 1,400°C. The electrochemical behaviour was investigated in 0.1 N H2SO4 solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The shrinkage decreased and densification has been increased with increasing pressure. The mechanical and electrochemical behaviour with pressure has been correlated with densification response and microstructure (pore type, volume and morphology). Highest densification (~92% theoretical) achieved at 600 MPa (compaction pressure) and 1,400°C (sintering temperature) resulted in excellent combination of tensile strength and ductility (456 ± 40 MPa, 25 ± 1.1%), while showing excellent corrosion resistance (0.1 mmpy or 4.7 mpy). © 2016 by De Gruyter 2016.

High Temperature Materials and Processes

Retraction of: Mechanical and Electrochemical Characterization of Super-Solidus Sintered Austenitic Stainless Steel (316L)

This study investigates the effect of heating mode on the sintering of Copper-SiC metal matrix composites containing up to 7.5 wt.% SiC. The sinterability of the Cu-SiC system consolidated in a 2.45 GHz multimode microwave furnace has been critically compared with that processed in a radiatively heated (conventional) furnace. As compared to conventional sintering, microwave processing has resulted in a greater densification. It was observed that an increase in SiC content resulted in a higher hardness of the materials for both the heating modes. For all compositions, the electrical conductivity and hardness of microwave-sintered Cu-SiC composites are higher than those of their conventionally sintered counterparts. © 2017 EDP Sciences.

Metallurgical Research & Technology

Conventional and microwave assisted sintering of copper-silicon carbide metal matrix composites: a comparison

The present work investigates the effect of sintering mode and graphene addition on the microstructural, mechanical and electrical properties of copper–graphene metal matrix composites reinforced with varying amounts (0.9, 1.8, 2.7 and 3.6 vol%) of graphene particles fabricated through powder metallurgy route. Sintering was carried out at 900 °C in 95%N2-5%H2 (forming gas) atmosphere with a heating rate of 5°/min for conventional and 20 °C/min for microwave with a holding time of 60 min in both cases. All the composites were found to couple well with microwave field and had resulted in 63% reduction in the processing cycle time as compared to the conventional process. Micro-structural analysis revealed the homogeneous distribution of graphene in copper matrix. Copper-graphene composites exhibited excellent wear resistance due to higher hardness and excellent lubricating nature of graphene. It was observed that porosity has a significant effect on the electrical conductivity values. © 2017 The Society of Powder Technology Japan

Advanced Powder Technology

An investigation on the effect of sintering mode on various properties of copper-graphene metal matrix composite

The present study examines the effect of sintering temperature and heating mode on densification, microstructure and mechanical properties of Fe-P alloys. The green compacts were heated conventionally and in microwave under 95%N2-5%H2 (forming gas) at 1120 °C and 1250 °C for 60 min. Both the compositions (Fe-1.5P and Fe-3P in wt%) were found to couple well in microwave field with rapid heating (∼ 40 °C min-1) and resulted in reduction of overall processing time by about 90% in comparison of conventional heating. Microwave sintering resulted in higher densification in case of Fe-P alloys. Moreover, an important feature of microwave and conventionally sintered samples was that their microstructures exhibited distinctly rounded pores. This resulted into improved corrosion and mechanical properties in general. © 2016 Elsevier Inc. All rights reserved.