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Fabrication of Ceramic-Metal Functionally Graded Materials
Engineering and Technology Journal, 2013
High order step wise functionally graded materials Al2O3-Ti are fabricated. These materials combine the high fracture toughness of Ti phase and the relatively low density of Al 2O3 and stand for candidate materials for harsh mechanical and thermal environments. The techniques of powder technology are utilized to fabricate these materials that composed of five graded layers of Al 2O3-Ti phases. Al2O3 increasing linearly across these layers (0, 25, 50, 75 and 100wt% respectively). The green specimens are composed of Al 2O3-TiH2 layers and the sintered specimens are composed of graded Al2O3-Ti. Spark Plasma Sintering technique is utilized for sintering of the graded green specimens. The best sintering conditions is found at 1500°C for 30 minute of sintering that gives apparent density of 4.25 g/cm 3 , porosity of 1.28% and diametric expansion of 1.58%. Optical microscopy shows gradual transition of phases at the interface of the graded layers.
Scientific Research and Essays, 2013
Whenever two or more dissimilar materials are bonded, large jump in the stresses occurred at the interface during the fabrication will leads to the delamination and poor load-bearing performance on the final structures. Functionally graded material (FGM) which has compositional and microstructure gradient along its thickness was introduced to be a great solution to this problem. Aiming for the best technique to be implemented, this paper presents an extensive review on the various fabrication techniques of FGMs composed by metallic and ceramic phases. Fabrication techniques in this field of work have incorporated many concepts from different background of gradation processes and consolidation or sintering processes. Each of these processes however has their own advantages and disadvantages. The best technique to be applied can be found by considering some critical issues highlighted in published literatures. This review concluded the powder metallurgy (PM) as the most suitable techn...
Advanced symmetrically graded ceramic and ceramic-metal composites
Journal of Materials Science, 2000
The potential of electrophoretic deposition as a shaping process of free-standing objects with a gradient in composition is investigated. The capability to produce relatively thick continuously graded ZrO 2 -Al 2 O 3 and WC-Co-Ti(C,N) discs was explored. After electrophoretic deposition, the dried deposits were cold isostatically pressed and pressureless sintered. In order to create a symmetric gradient profile along the thickness of the plates, a mathematical model for the EPD process was developed in order to predict the composition and slope of the gradient profile in the discs from the starting composition of the suspension, the EPD operating parameters and the powder-specific EPD characteristics. The sintered graded materials have a continuous variation in composition, microstructure and mechanical properties. In the illustrated ZrO 2 -Al 2 O 3 example, the ZrO 2 content increases from 0 vol% on the outer surface up to 25 vol% in the core. For the WC-Co-Ti(C,N) discs, the Ti(C,N) content decreases from 5 wt% on the outer edge to 0 wt% in the bulk of the material. In both materials, a hard outer rim and a tough core are obtained. Finally, the residual surface stresses of the densified graded ZrO 2 -Al 2 O 3 discs were investigated. C 2004 Kluwer Academic Publishers
Overview of functionally graded materials
Computational Structural Mechanics
The present work looked into about Functionally Graded Materials (FGMs) as the practically evaluated materials (FGMs), a creative material has a place with a class of cutting edge material with changing properties over evolving measurement. The last properties of FGM are one of a kind and not quite the same as any of the individual material that shapes it. Normally, under brutal temperature conditions, the ordinary materials (metals or earthenware production) alone might not survive which prompted improvement of a development material i.e functionally graded material which is prepared to do withstanding high temperature under cruel conditions. Practically evaluated materials are generally utilized as a part of air ships, space vehicles and different items working at lifted temperatures. The range of utilization of FGMs is required to increment as the expense of material improving so as to prepare and manufacture procedures are diminished these procedures.
Advances in Functionally Graded Ceramics – Processing, Sintering Properties and Applications
Advances in Functionally Graded Materials and Structures, 2016
In multilayered structures, sharp interface is formed between the layers of dissimilar materials. At this interface, the large difference in thermal expansion coefficients of the two dissimilar materials generates residual thermal stresses during subsequent cooling. These stresses lead to cracking at the interface, and these cracks lead to the deterioration of mechanical properties, and finally crack propagation leads to the delamination of the multilayered structure. Scientific progress in the field of material technology, and the continuing developments of modern industries have given rise to the continual demand for ever more advanced materials with the necessary properties and qualities. The need for advanced materials with specific properties has brought about the gradual transformation of materials from their basic states (monolithic) to composites. Recent advances in engineering and the processing of materials have led to a new class of graded multilayered materials called Functionally Graded Materials (FGMs). These materials represent a second generation of composites and have been designed to achieve superior levels of performance. This chapter looks at the best processing technologies and the uses and applications of the advanced, high quality products generated, and also presents an extensive review of the recent novel advances in Functionally Graded Ceramics (FGCs), their processing, properties and applications. The manufacturing techniques involved in this work have involved many concepts from the gradation, consolidation and different sintering processes. Each technique, however, has its own characteristics and disadvantages. In addition, the FGC concept can be applied to almost all material fields. This chapter covers all the existing and potential application fields of FGCs, such as engineering applications in cutting tools, machine parts, and engine components, and discusses properties of FGCs such as heat, wear, and corrosion resistance plus toughness, and their machinability into aerospace and energy applications.
Engineering and Technology Journal
This work includes the design and preparation of a(Low carbon steel / AL 2 O 3) stepwise functionally graded crown part of an internal combustion engine piston. Powder technology technique, has been studied to improve engine thermal efficiency by creating semi adiabatic combustion chambers, where ceramic phase facing the hot combustion gases, while metallic phase assembling with other parts of the piston. Finite element method ABAQUS program had been used to minimize nucleated residual stresses generated under fabrication process and service work conditions by designing the compositional graded of stepwise FGM within specific dimensions, in addition to temperature distribution across FGM thickness. Then the fabricated specimens had SEM imaging, physical and mechanical property inspection. The results also show that linear transition from metal to ceramic structure can provide minimum residual stresses under all conditions, using stepwise FGM can improve engine heat efficiency by doubling the crown surface temperature,(622) ºC, comparing with steel crown, (322) ºC, under the same applied heat flux. Physical inspections show limited relative density, (48.5) %, with high total porosity structure, (53.3) %, can be performed by this fabrication method. Mechanical tests results show that the layers" hardness increase with increasing ceramic content, and decrease with increasing pores percentage. Compression test shows the ability of suggested stepwise FGM to withstand service work stresses of combustion chamber without failure.
Metal Based Functionally Graded Materials
2010
References 69 i FOREWORD The concept of functionally graded materials (FGMs) introduced a class of highly engineered structures tailored to specific properties, resulting of compositional changes in used materials. The necessity to bring into practice new materials appears crucial with, for instance, space vehicles: on the surface side the skin plates should have very good heat-resistance, on the inside, however, -high mechanical qualities (e.g. toughness) were needed. The problem was successfully solved in Japan in the mid of 1980s by manufacturing specific composite: metallic matrix and ceramic particles with graded distribution of these particles. That solution is close with ingenious structural systems in some plants, e.g. bamboo. After 20 years of intensive research and practical applications, the field of FGMs is still in development and a precise definition of that new class of materials is till now not accepted. Modeling of FGMs is recognized as indispensable step in designing at the microstructural level to meet specific requirements of an intended application. Many production technologies were proved to be useful for practical adoption.
FABRICATION OF FUNCTIONALLY GRADED COMPOSITE MATERIAL USING POWDER METALLURGY ROUTE: AN OVERVIEW
Functionally Graded Composite Material (FGCMs) are inhomogeneous materials, consisting of two (or more) different materials, with an engineered gradient along the thickness direction having a continuously varying spatial composition. Keeping in mind the wide areas of application and the probable scope of such materials, some existing problems are discussed. As part of the present investigation, a simple experimentation involving Al-SiC and Al-Al 2 O 3 FGCM, by powder metallurgy (PM) route has been carried out and discussed. The effect of SiC and Al 2 O 3 addition on the density of Aluminium, in the proposed functionally graded composite material and an overview of the current status of research on FGCMs including its future development is presented here. This review is about establishing powder metallurgy (PM) as a better technique for large scale production and up scaling of FGCM. This was further strengthened after considering the benefits of the technique such as process cost efficiency, authenticity of the functional application of the process and high adequacy of the process to control the quality of the FGM.
Nanotechnology Reviews, 2022
Functionally graded porous (FGP) nanocomposites are the most promising materials among the manufacturing and materials sector due to their adjustable physical, mechanical, and operational properties for distinctive engineering applications for maximized efficiency. Therefore, investigating the underlying physical and materialistic phenomena of such materials is vital. This research was conducted to analyze the preparation, fabrication, applications, and elastic properties of functionally graded materials (FGMs). The research investigated for both porous and nonporous synthesis, preparation, and manufacturing methods for ceramics, metallic, and polymeric nanocomposites in the first section, which is followed by deep research of the development of elastic properties of the above-mentioned materials. Main nano-reinforcing agents used in FGMs to improve elastic properties were found to be graphene platelets, carbon nanotubes, and carbon nanofibers. In addition, research studied the impa...
A Review of Functionally Graded Materials: Fabrication Processes and Applications
2018
Functionally graded materials (FGMs) are materials that possess variance in properties across the geometry of the material. They are a class of materials developed from the existing knowledge of material alloying. This paper discusses the evolution and the background study of FGMs. The different FGMs processing techniques and their comparative advantages were discussed. Furthermore, the paper classified FGMs based on the principle of their manufacturing method. Various application areas of FGMs were discussed.