Development of magnesium/(yttria+nickel) hybrid nanocomposites using hybrid microwave sintering: Microstructure and tensile properties (original) (raw)
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Journal of Alloys and Compounds, 2011
In the present study, magnesium nanocomposites were fabricated using magnesium as matrix and nanoyttria as reinforcement. Nanocomposites with 0.2 and 0.7 vol.% of Y 2 O 3 particulates with an average size of 29-50 nm were synthesized blend-press-sinter powder metallurgy technique followed by hot extrusion. Conventional slow heating and microwave assisted rapid heating sintering techniques were used. Microstructural characterization of the materials revealed fairly uniform distribution of reinforcement with the presence of minimal porosity in all of the processed materials, while significant grain refinement in the cases of conventionally sintered materials. Tensile properties characterization of the conventional and microwave sintered nanocomposites revealed that significant and resembling increase in the 0.2% yield strength and ultimate tensile strength of magnesium matrix with the increasing presence of reinforcement. The ductility and work of fracture of magnesium matrix increased significantly in the case of conventionally sintered nanocomposites when compared to the microwave assisted sintered nanocomposites.
Journal of Materials Science, 2008
The present study establishes that extrusion ratio has a critical role in enhancing microstructural and mechanical characteristics of commercially pure magnesium and a magnesium-based nanocomposite. The study reveals that the best microstructural and mechanical characteristics can be achieved in a Mg/Y 2 O 3 nanocomposite provided it is extruded at a ratio higher than a critical extrusion ratio (19:1). An extrusion ratio at 25:1 is found to be the ratio in the present study which leads to significant enhancement in microstructural characteristics (low porosity and good distribution of particulates) and mechanical properties (microhardness, 0.2% YS and UTS) of a Mg/2 wt.%Y 2 O 3 nanocomposite. Results of this study also show very close relationship between microhardness and strengths (0.2% YS and UTS) for both pure magnesium and Mg/Y 2 O 3 composite extruded at different extrusion ratios.
Materials Science and Technology, 2005
In the present study, magnesium composites reinforced with different volume fraction of submicron size Al 2 O 3 particulates were synthesised using powder metallurgy technique incorporating an innovative microwave assisted rapid sintering technique. The sintered materials were subsequently hot extruded for characterisation in terms of microstructural, physical and mechanical properties. Microstructural characterisation results revealed a reasonably uniform distribution of Al 2 O 3 particulates, minimal porosity and good matrix reinforcement interfacial integrity. The average coefficient of thermal expansion (CTE) value for Mg-Al 2 O 3 composites was found to decrease with increasing amount of submicron Al 2 O 3 particulates. Mechanical characterisation of the composites revealed an increase in hardness, elastic modulus, 0. 2% YS and ultimate tensile strength (UTS) with the increase in amount of alumina particulates. Ductility exhibited the reverse trend. An attempt is made in the present study to correlate the effect of the presence of submicron alumina and its increasing amount with the microstructural, physical and mechanical properties of magnesium.
Journal of Alloys and Compounds, 2015
The present study illustrates the structural and mechanical properties of magnesium composites containing Ni 50 Ti 50 metallic glass reinforcement particles. Novel Mg-composites containing 3, 6 and 10 vol.%Ni 50-Ti 50 amorphous particulates were synthesized using the microwave assisted rapid sintering technique followed by hot extrusion. The developed Mg-composite materials were investigated for their microstructural and mechanical properties. Microstructural studies revealed the retention of amorphous structure of Ni 50 Ti 50 reinforcement and its fair distribution in developed Mg/Ni 50 Ti 50 composites. Mechanical property evaluation under indentation and compression loads showed significant enhancement in strength properties (microhardness:+78%, 0.2CYS:+79%, UCS:+70%, 0.2TYS:+95%, UTS:+50%) without compromising the compressive ductility. For the first time, tensile properties of such amorphous particles reinforced Mg-composites were studied and the results showed 9898% increase in 0.2TYS and 9850% increase in UTS. The tensile ductility was adversely affected. However, the obtained values are comparable to that of conventional Mg-composites. The observed mechanical response discussed in terms of structure-property relationship highlights the efficacy of amorphous Ni 50 Ti 50 reinforcement particles and the energy efficient microwave sintering approach to produce high performance magnesium composites.
Effect of copper nano particles on high temperature tensile behavior of Mg-Y2O3 nanocomposite
Metals and Materials International, 2015
Magnesium reinforced with 0.7 volume percentage of yttria is considered to be one of the most promising light weight structural nanocomposite materials, whose performance was further enhanced with incorporation of 0.3 volume percentage of nano copper particles. Elongation-to-fracture tensile test revealed that the nano copper particle effectively maintained strengthening effect on magnesium-yttria nanocomposite at up to 100°C and gradually diminished with further increase in test temperature used in this study. Nano copper particle induced impressive enhancement in magnesium-yttria nanocomposite and led to their potential near net shape fabrication in to intricate shaped objects at a substantially low temperature.
Effect of hybrid reinforcement on the high temperature tensile behavior of magnesium nanocomposite
International Journal of Materials Research, 2015
In the present study, results revealed that hybrid (0.7 % yttria + 0.3 % copper) nano-particle reinforcement has a significant strengthening effect on commercially pure magnesium reaching 100 8C, which gradually diminishes with further increase in temperature. Due to the presence of reinforcement particles, magnesium matrix also completely recrystallizes at 100 8C. Hybrid nano-reinforcement also assisted in the deformation process and achieved large ductility at a relatively low temperature.
TMS/TMS2015, 2015
than steel is an attractive and a viable candidate for the fabrication of lightweight structures. Being the designers' choice for weight critical applications, extensive research efforts are underway into the development of magnesium metal matrix composites (Mg-MMCs) through various cost-effective fabrication technologies. In recent years, there has been a progressive advancement in utilizing the microwave energy to consolidate powder materials and the present study accentuates the use of energy efficient and environment friendly microwave sintering process to synthesize magnesium based composite materials. The processing advantages of the innovative and cost effective microwave assisted bidirectional rapid sintering technique followed by hot extrusion are first briefly introduced. Subsequently, the properties of various Mg-MMCs (containing micro/nano sized, ceramic/metal/amorphous reinforcement particles) synthesized using this technique are presented. Special emphasis has been made on the commending properties displayed by the nanoparticle reinforced Mg composites (Mg-MMNCs). Finally, an account of ongoing research initiatives in the development of novel light weight Mg-composites is highlighted.
A Review on Mechanical Properties of Magnesium Based Nano Composites
AIP Conference Proceedings, 2018
A review was done on Magnesium (Mg) based composite materials reinforced with different nano particles such as TiO2, Cu, Y2O3, SiC, ZrO2 and Al2O3. TiO2 and Al2O3 nanoparticles were synthesised by melt deposition process. Cu, Y2O3, SiC and ZrO2 nanoparticles were synthesised by powder metallurgy process. Composite microstructural characteristics shows that the nano-size reinforcements are uniformly distributed in the composite matrix and also minimum porosity with solid interfacial integrity. The mechanical properties showed yield strength improvement by 0.2 percentage and Ultimate tensile strength (UTS) was also improved for all the nano-particles. But UTS was adversely affected with TiO2 reinforcement while ductility was increased. With Cu reinforcement elastic modulus, hardness and fracture resistance increased and improved the coefficient of thermal expansion (CTE) of Mg based matrix. By Y2O3 reinforcement hardness, fracture resistance was improved and ductility reached maximum by 0.22 volume percentage of Y2O3 and decreased with succeeding increase in Y2O3 reinforcement. The readings exposed that mechanical properties were gathered from the composite comprising 2.0 weight percentage of Y2O3. Ductility and fracture resistance increased with ZrO2 reinforcement in Mg matrix. Using Al2O3 as reinforcement in Mg composite matrix hardness, elastic modulus and ductility was increased but porosity reduced with well interfacial integrity. Dissipation of energy in the form of damping capacity was resolved by classical vibration theory. The result showed that an increasing up to 0.4 volume percentage alumina content increases the damping capacity up to 34 percent. In another sample, addition of 2 weight percentage nano-Al2O3 particles showed big possibility in reducing CTE from 27.9-25.9×10 6 K 1 in Magnesium, tensile and yield strength amplified by 40MPa. In another test, Mg/1.1Al2O3 nanocomposite was manufactured by solidification process followed by hot extrusion. Results showed that strengthening effect was maintained up to 150 C and fracture characteristics of Mg composite transformed from brittle to mixed ductile mode and fully ductile in attendance of nano-Al2O3 particulates.
In this study, magnesium composites with nano-size boron nitride (BN) particulates of varying contents were synthesized using the powder metallurgy (PM) technique incorporating microwave-assisted two-directional sintering followed by hot extrusion. The effect of nano-BN addition on the microstructural and the mechanical behavior of the developed Mg/BN composites were studied in comparison with pure Mg using the structure-property correlation. Microstructural characterization revealed uniform distribution of nano-BN particulates and marginal grain refinement. The coefficient of thermal expansion (CTE) value of the magnesium matrix was improved with the addition of nano-sized BN particulates. The results of XRD studies indicate basal texture weakening with an increase in nano-BN addition. The composites showed improved mechanical properties measured under micro-indentation, tension and compression loading. While the tensile yield strength improvement was marginal, a significant increase in compressive yield strength was observed. This resulted in the reduction of tension-compression yield asymmetry and can be attributed to the weakening of the strong basal texture.