Effects of Ni foil thickness on the microstructure and tensile properties of reaction synthesized multilayer composites (original) (raw)
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Journal of Composite Materials, 2019
This research studies the structure and mechanical properties of Ni/Ti multilayered composites produced from commercial pure Ni and Ti foils by accumulative roll-bonding technique. To investigate these properties, scanning electron microscopy, Vickers microhardness, and uniaxial tensile tests were conducted at different processing cycles. Studies showed that in terms of structure, Ni and Ti layers maintain their continuity even up to 10 cycles of accumulative roll-bonding. Moreover, the energy-dispersive spectroscopy in scanning electron microscopy detected no deformation induced diffusion or reactive interfacial zones. It was found that by increasing the accumulative roll-bonding cycles, tensile and yield strengths as well as the hardness of the composite enhance and the total elongation reduces continuously.
Ni/Ti and Ni/Al Laminated Composites Produced by ARB and Annealing: Microstructural Aspects
Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, 2015
Accumulative roll bonding (ARB) is a combination of forming and bonding processes. So, this is a high promising technique to produce bulk solid materials composed of more than one constituent. ARB has been applied to strengthen metals and to produce laminated metal-metal or nonmetal-metal composites, e.g. intermetallic composites, shape memory alloys or reactive foils [1, 2]. Since ARB is performed at room temperature, the formation of new phases can be avoided. This technique is also capable of mass production and it can fabricate thick foils, using simple and cheap equipment. This essay compares two bimodal multilayer foils: Ni/Ti and Ni/Al. Input materials include foils of 99.98 wt% Ni-125 µm thick, 99.00 wt% Al-200 µm thick and 99.6 wt% Ti-200 µm thick. Rolling was done with a strain rate of 20 s-1 at room temperature. Rolled batches after 4 and 10 cycles were characterized by optical and scanning electron microscopies. Energy dispersive spectroscopy (EDS) as chemical analysis technique was used to identify phases evolved in the multilayers during processing. Electron backscattering diffraction (EBSD) technique also assisted phase identification.
Tensile properties and fracture behavior of nanocrystalline Ni3Al intermetallic foil
Scripta Materialia, 2006
Fully dense nanocrystalline Ni 3 Al intermetallic foil was successfully produced from as-cast coarse-grained sheet by heavy rolling at liquid nitrogen temperature and subsequent recrystallization. The mechanical properties and fracture behavior of the nanocrystalline foil with grain size about 20 nm were derived from uniaxial tension tests at room temperature. Typically, the nanocrystalline foil exhibits significantly higher yield strength ($2.6 GPa), and reduced tensile elongation ($4.0%) relative to its microcrystalline counterpart (yield strength 0.7GPaandtensileelongation0.7 GPa and tensile elongation 0.7GPaandtensileelongation22%).
The Effect of Strain on the Formation of an Intermetallic Layer in an Al-Ni Laminated Composite
Metals
In the present work, the influence of strain on phase formation at the Al/Ni interface was investigated during cold roll bonding and annealing. A sandwich sample composed of an Al-Ni-Al stack was cold rolled with reductions in the range of 50% to 90%, followed by annealing at 450 • C for 60 min. The crystallography of the annealed sandwich samples was analyzed by XRD (X-ray diffraction), whereas the microstructure was studied by scanning electron microscopy, equipped with EDS (energy dispersive spectrometer) analysis, and optical microscope. In the annealed samples, the intermetallic phase Al 3 Ni has formed at the Ni/Al interface, preferentially on the Al side of the interface. It is found that the applied strains did not have an effect on the type of intermetallic phase that was formed. However, the rolling reduction has a significant effect on the morphology of the intermetallic layer, as it was observed that after the lowest reduction of 50% only some scattered intermetallic nuclei were present, whereas at the highest rolling reduction of 90% a continuous intermetallic layer of 4.1 µm was exhibited. The formation of the intermetallic layer is discussed in terms of Al and Ni diffusion at the interface and irregular nature of the Al/Ni bonded interface after rolling reductions.
Archives of Metallurgy and Materials, 2000
ABSTRACT Dense lanthanum cobaltite ceramics with different microstructures were prepared using several processing procedures, including chemical and ceramic synthesis routes. XRD, SEM, dilatometry, total electrical conductivity and oxygen permeability measurements were used for the characterization of these materials. Submicrometer size LaCoO3−δ powders obtained via a cellulose-precursor technique or a combustion synthesis process showed much higher sinterability and poor compactability with respect to the powder prepared by the standard ceramic procedure. The influence of the processing route on crystal lattice, electronic conductivity and thermal expansion of LaCoO3−δ ceramics was negligible. At the same time, the preparation technique significantly affects the ceramic microstructure and the oxygen ionic conductivity. LaCoO3−δ membranes prepared via the standard ceramic technique, involving higher sintering temperatures, exhibit significantly higher oxygen permeation fluxes than ceramics prepared from organic precursors. This behavior was attributed to the effect of grain-boundary resistivity to ionic transport, which decreases with increasing sintering temperature and grain size, as commonly found for oxide solid electrolytes.
Journal of Materials Engineering and Performance, 2012
The present investigation is an attempt to develop metal-intermetallic laminate composites based on Ni-Al system. In this study, Ni sheets and Al foils have been used for the development of Ni-Al laminate using accumulative roll-bonding technique at 773 K. The laminate composites were then subjected to the controlled annealing to affect reactive diffusion at the Ni/Al interface leading to intermetallic compound formation. The accumulative roll-bonded laminates showed good bonding of layers. Annealing treatment at 773 K led to formation of reaction product and maintained the interface integrity. A qualitative compositional analysis at the interfaces reflected the formation of Al-Ni compounds, and a gradual compositional gradient also across the interface. This process seems to be of promise so far as the continuous production of large scale metal-intermetallic laminate composites is concerned.
Intermetallics, 2017
Pure nickel and Nickel Alloy-X based Metallic-Intermetallic Laminate (MIL) composites were fabricated and investigated for their microstructure evolution, growth kinetics and microhardness distribution across the intermetallic/metal interfaces. Multi-phase layer structure with parabolic growth kinetics is shown in the nickelbased MIL composites. A two-phase eutectic layer along with a uniform layer form in the Alloy-X based MIL composites, which shows a mixed growth kinetic mechanism. The microhardness distribution across the intermetallic/metal interface of the two MIL composites was investigate with respect to the effects of texture and microstructure of the intermetallic phases. A simple intermetallic growth model is developed and validated for predicting the phase formation in binary or ternary reactions for synthesis of these MIL composites.
The International Journal of Advanced Manufacturing Technology, 2019
Modern day technology demands consistent and frequent advancements in materials for specialized applications. Nickel aluminide is one of such materials with distinctive properties that make them particularly suitable for high temperature applications especially in aerospace industries. However, the lack of ambient temperature ductility of this intermetallic has greatly restricted its applicability in service. In this review, the various efforts of researchers in solving this major limitation of nickel aluminides is evaluated and summarized, with particular emphasis on reinforcement types and processing methods that have been explored over the years.
Microstructure evolution in pure Ni and Invar-based Metallic-Intermetallic Laminate (MIL) composites
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2017
Metallic-Intermetallic Laminate composites of Ni/Al and Invar/Al were fabricated and investigated for the microstructure evolution, growth kinetics and microhardness distribution across the intermetallic/metal interfaces. A single-phase intermetallic layer, with parabolic growth kinetics, is shown in the pure Ni/Al reaction, while a complex multi-phase layer (eutectic and uniform layer) with mixed growth kinetic mechanisms is identified in the Invar/Al reaction by EDS and EBSD analysis. Primary growth and texture of the intermetallic phase in Invar-based MIL are analyzed with respect to their effects on the microhardness distribution across the metal/intermetallic layer. The intermetallic yield rate of the two different Ni-aluminide reactions are calculated and demonstrated to be reliable for predicting the final intermetallic layer thickness in Ni-based MIL composites.