Manas Mohan Mahapatra

Bio: Manas Mohan Mahapatra is an academic researcher from Indian Institute of Technology Bhubaneswar. The author has contributed to research in topics: Welding & Ultimate tensile strength. The author has an hindex of 36, co-authored 187 publications receiving 3657 citations. Previous affiliations of Manas Mohan Mahapatra include Indian Institutes of Technology & Indian Institute of Technology Guwahati.

Recent progress in aluminum metal matrix composites: A review on processing, mechanical and wear properties

Abstract: The necessity for high performance and low-cost materials caused the researchers worldwide to switch the focus from monolithic to composite materials. In the recent pasts, a significant effort has been made in this direction to fabricate numerous combinations of metal matrix composites. Among the MMCs, aluminum-based composites are treated as the most promising structural materials due to their high corrosion, wear resistance, specific modulus, and weight for automobile and aerospace applications. Aluminum MMCs were produced by various fabrication process after considering different reinforcement particles, such as borides, carbides, oxides, nitrides, and their combinations. Aluminum MMCs revealed excellent mechanical and wear characteristics owing to the formation of stable reinforcement particles in the composites. In the present review article, recent advances in processing, microstructure, wear, and mechanical characterization of aluminum composites reinforced with different particles are addressed. The future scope of these composites is also briefly discussed at the end of the manuscript.

Evolution of phases in P91 steel in various heat treatment conditions and their effect on microstructure stability and mechanical properties

Abstract: To achieve high thermal efficiency, modern day thermal power plants operate at higher operating temperature and pressure which necessitates use of steels with high creep rupture strength such as modified 9Cr-1Mo steels. In the present study, the evolution of phases in modified 9Cr-1Mo P91 steel and their effects on microstructural stability and mechanical properties have been studied for specimens that were subjected to different thermal heat treatment conditions. The main focus has been to study the effect of heat treatment temperature ranging from 623 K to 1033 K (350–760 °C) on P91 steel. Further, the effect of furnace cooling, water quenching, tempering at 1273 K (1000 °C) and austenitizing on the mechanical properties and microstructure has been studied. The techniques used for material characterization were scanning electron microscopy (SEM), optical microscopy (OM) and X-ray diffraction. For low tempering temperature, i.e. 623 K (350 °C), M 23 C 6 , M 3 C, M 7 C 3, and MX precipitates have been observed with high yield strength (YS), tensile strength (UTS), hardness and low toughness. In the high temperature range, 923–1033 K (650–760 °C), fine MX, M 7 C 3 , M 23 C 6 , M 2 X, and M 3 C precipitates have been observed with low YS, UTS, hardness and high toughness. The steel tempered at 1033 K (760 °C) was observed to be having best combination of YS, UTS, hardness, toughness and ductility.

Some studies on P91 steel and their weldments

Abstract: In present research article, microstructure evolution in P91 steel and their weldments are reviewed in as-virgin and heat treatment and creep exposure condition. The thermal stability of P91 steel is derived from solid solution strengthening, sub-grain hardening and precipitation hardening. The initial microstructure plays an important role in deciding the mechanical properties of P91 steel and their weldment in long-term ageing and creep exposure condition. Effects of various alloying elements present in P91 steel and their related phase have also been discussed in details. The role of grain coarsening, Cr/Fe ratio, lath widening and dislocation density on creep rupture life of base metal and weldments are discussed. The combined effects of lath martensitic microstructure, residual stress and diffusible hydrogen content on performance of P91 steel material are also discussed.

Study of the fracture surface morphology of impact and tensile tested cast and forged (C&F) Grade 91 steel at room temperature for different heat treatment regimes

Abstract: Cr-Mo creep strength enhanced ferritic (CSEF) steels are mainly used in nuclear reactors and ultra-supercritical (USC) power plants for superheater tubes and header. The present research deals with the analysis of fracture surface of the tensile and impact tested specimen of cast and forged (C&F) modified 9Cr-1Mo (P91) steels, which are subjected to different heat treatment regimes. The heat treatment temperatures were 350 °C, 650 °C, 760 °C and 1000 °C, respectively. The heat treatment was carried out a particular temperature for 2 h duration. The fracture surface of tensile and impact tested specimen were also studied for a varying time duration from 2 h to 8 h for a fixed tempering temperature of 760 °C. The heat treatment effect on tensile properties, toughness, Vickers hardness and particle size was also studied. Heat treatment has a noticeable effect on mechanical properties of C&F Grade 91 (X10CrMoVNNB9-1) steel. Fracture morphology is strongly affected by the microstructure and presence of secondary phase particles. The fracture surface was analyzed by using the field-emission scanning electron microscope (FE-SEM). The fractured tensile sample mainly indicates the presence of transgranular ductile dimples and transgranular cleavage facets for heat treatment temperatures of 350 °C, 1000 °C and 1040 °C. The percentage of cleavage facets on the tensile fracture surface was found to decrease for sample heat treated at 760 °C. Less amount of ductile dimples was noticed on the fracture surface for the samples heat treated at 650 °C and 760 °C (furnace-cooled). The so-called ‘splitting’ fracture was noticed for the sample heated at 760 °C. The ‘splitting’ fracture becomes more pronounced with the increase in tempering duration from 2 h to 8 h. The sample heat treated for 1000 °C, mainly indicates the cleavage facets on the fracture surface. The fracture mode of impact tested specimen is more complex and shows both ductile dimple tearing and quasi-cleavage facets for heat treatment temperature of 650 °C, 760 °C and as-received condition. The impact failure zone of sample heat treated at 350 °C and 1000 °C indicates the presence of so-called ‘river pattern’ on the fracture surface.

Thermal Barrier Coatings—A State of the Art Review

Abstract: Thermal barrier coatings (TBCs) have seen considerable advancement since the initial testing and development of thermal spray coating. Thermal barrier coatings are currently been utilized in various engineering areas which include internal combustion engines, gas turbine blades of jet engines, pyrochemical reprocessing units and many more. The development of new materials, deposition techniques is targeted at improving the life of the underlying substrate. Hence, the performance of the coating plays a vital role in improving the life of substrate. The scope for advancement in thermal barrier coatings is very high and continuous efforts are being made to produce improved and durable coatings. Thermal barrier coatings have the potential to address long term and short-term problems in gas turbine, internal combustion and power generation industry. The study of thermal barrier coating material, performance and life estimation is a critical factor that should be understood to introduce any advancement. The present review gives an overview of the thermal spraying techniques and current advancements in materials, mechanical properties, understanding the high temperature performance, residual stress in the coating, understanding the failure mechanisms and life prediction models for coatings.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Aluminium matrix hybrid composites: a review of reinforcement philosophies; mechanical, corrosion and tribological characteristics

Abstract: Aluminium hybrid composites are a new generation of metal matrix composites that have the potentials of satisfying the recent demands of advanced engineering applications. These demands are met due to improved mechanical properties, amenability to conventional processing technique and possibility of reducing production cost of aluminium hybrid composites. The performance of these materials is mostly dependent on selecting the right combination of reinforcing materials since some of the processing parameters are associated with the reinforcing particulates. A few combinations of reinforcing particulates have been conceptualized in the design of aluminium hybrid composites. This paper attempts to review the different combination of reinforcing materials used in the processing of hybrid aluminium matrix composites and how it affects the mechanical, corrosion and wear performance of the materials. The major techniques for fabricating these materials are briefly discussed and research areas for further improvement on aluminium hybrid composites are suggested.

A review on the production of metal matrix composites through stir casting – Furnace design, properties, challenges, and research opportunities

Abstract: Stir casting is one of the most suitable processes for producing Metal Matrix Composites (MMCs) because of its simplicity, proven process, lower cost of production and mass production capability. This paper reviews all the significant attributes of stir casting process such as furnace design, properties of the composites, challenges in the production of the composites as well as the potential research opportunities in the production of composites. We have also provided recommendations for the furnace design, selection of matrix and reinforcement materials as well as process parameters and additives, which makes the review novel. In order to provide a background for any reader interested in the production processes for MMCs, we have also discussed the various approaches in the introductory section briefly. Based on the critical assessment of the literature, especially the mechanical properties of the produced MMCs, a bottom tapping stir casting furnace, preferably with electromagnetic and ultrasonic stirrer along with squeeze attachment is recommended for the production of MMCs.

Hydrogen embrittlement in different materials: A review

Abstract: Hydrogen embrittlement (HE) is a widely known phenomenon in high strength materials. HE is responsible for subcritical crack growth in material, fracture initiation and catastrophic failure with subsequent loss in mechanical properties such as ductility, toughness and strength. This hydrogen is induced in the material during electrochemical reaction and high-pressure gaseous hydrogen environment. LIST, SSRT and TDS techniques are performed to know the effect in mechanical properties and amount of hydrogen available in the material. For microstructure examination SEM, FESEM and TEM are performed to know the effect of hydrogen in the internal crystal structure. Also, various mechanisms which are responsible for crack growth and final fracture are discussed. This paper deals with HE definition, mechanisms which causes HE, subcritical crack growth, the concentration of hydrogen measurement and prevention activities are discussed which act as a barrier for hydrogen diffusion.