Effect of hybridizing micron-sized Ti with nano-sized SiC on the microstructural evolution and mechanical response of Mg-5.6Ti composite (original) (raw)
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Materials, 2019
In the present study, Mg nanocomposites with a high volume fraction (10 vol %) of SiC particles were fabricated by two approaches: mechanical milling and mixing, followed by the powder consolidation steps, including isostatic cold pressing, sintering, and extrusion. A uniform distribution of the high content SiC particles in a fully dense Mg matrix with ultrafine microstructure was successfully achieved in the mechanically milled composites. The effect of nano- and submicron-sized SiC particles on the microstructure and mechanical properties of the nanocomposites was evaluated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), and X-ray diffractometry (XRD) were used to characterize microstructures of the milled and mixed composites. Mechanical behavior of the Mg composites was studied under nanoindentation and compressive loading to understand the effects the microstructural modification on the strength and ductility o...
Journal of Magnesium and Alloys, 2014
In this study, the effects of hybridizing micron-sized titanium particles with nano-sized boron carbide particles on the microstructural and mechanical properties of MgeTi composite were investigated. Microstructural characterization revealed grain refinement attributed to the presence of uniformly distributed micro-Ti particles embedded with nano-B 4 C particulates. Electron back scattered diffraction (EBSD) analyses of the Mge(Ti þ B 4 C) BM hybrid composite showed relatively more localized recrystallized grains and lesser tensile twin fraction, when compared to MgeTi. The evaluation of mechanical properties indicated that the best combination of strength and ductility was observed in the Mge(Ti þ B 4 C) BM hybrid composite. The superior properties of the Mge(Ti þ B 4 C) BM hybrid composite when compared to MgeTi can be attributed to the presence of nano-reinforcement, the uniform distribution of the hybridized particles and the better interfacial bonding between the matrix and the reinforcement particles achieved by nano-B 4 C addition.
An Investigation on the Mechanical Properties of Al-Mg2Si-SiC Hybrid Composites
Iran International Aluminum Conference (IIAC2016), 2016
Aluminum hybrid metal matrix composites are the field of interest of researchers because they are widely used in aerospace and automobile industries. A hybrid composite benefits the properties of two or more reinforcement materials and could contain unique physical, mechanical and tribological properties which are not achievable in other materials. In this study different amounts of SiC microsize (37 μm) particles were added to Al-Mg2Si composite using stir casting method. Then, hot extrusion was applied to the specimens. Finally, the effect of different amounts of SiC on the mechanical properties of Al-Mg2Si in-situ composite was investigated. The microstructure characteristics of the composite was studied using optical and scanning electron microscopy. The results showed that SiC particles had a good dispersion in the Al-Mg2Si matrix. The hardness increased from 110 for the bas composite to 135 brinell for the composite containing 9 wt. % SiC. The amounts of YS and UTS of the Al-Mg2Si composite was 90 and 160 MPa respectively and the addition of 9 wt. % SiC enhanced these values to 125 and 260 MPa respectively. However, the addition of SiC reduced the elongation from 6.7 % to 1 %. Moreover, the addition of 9 wt. % SiC increased the ultimate compressive strength from 280 to 430 MPa.
Mechanical and wear behaviour of Mg–SiC–Gr hybrid composites
Journal of Magnesium and Alloys, 2016
The present research deals with development and characterisation of magnesium-SiC-Gr hybrid composites through powder metallurgy route. Morphology analysis of the magnesium and reinforcement powder particles has been carried out using particle size analyser (PSA) and X-ray diffraction (XRD), and then the mixed powders were analysed through scanning electron microscope (SEM). The developed composite exhibit increased hardness when compared to base material, which could be attributed to the presence of hard SiC. Furthermore, a slight decrease in hardness is observed for the hybrid composite when compared to Mg-SiC composite due to the presence of soft Gr particles. The tribological properties of the developed composite materials were investigated using pin-on-disc wear test apparatus under dry sliding conditions. The wear resistance of the developed composites improved significantly than that of the magnesium matrix due to the upright effect offered by both of the reinforcements. The SEM analysis was carried out on the worn out surfaces for better understanding of wear mechanisms. 5% Gr reinforced Mg-10SiC composites confer better wear resistance among the developed composites.
Materials Science and Engineering: A, 2000
The microstructure and heterogeneous nucleation phenomena in cast SiC particles reinforced magnesium composite have been studied using optical and transmission electron microscopy (TEM). The microstructure of magnesium composites showed that most SiC particles were pushed and segregated at the grain boundaries while few SiC particles (3%) were entrapped in the magnesium grain. The SiC particles in the magnesium composite were identified as 6Ha-SiC structure. Stacking faults and pits defects were also observed within the SiC particles. The primary magnesium phase which heterogeneously nucleated on the SiC particle surface has been identified with a small lattice disregistry (2.3%) while their crystallographic orientation relationship was (101( 0) Mg //(0001) SiC . Examination of the composite interface indicated that the eutectic and Cu 5 Zn 8 phases were able to wet the SiC particles and heterogeneously nucleate on the SiC particles while the crystallographic orientation relationships between them were (011( 1) SiC //(110) Mg17Al12 and (0001) SiC //(001) Cu5Zn8 , respectively. Finally, the factors that influence the heterogeneous nucleation of primary magnesium phase, eutectic and Cu 5 Zn 8 phases on the SiC particles are discussed.
The effect of SiC – particles – reinforced MgO composites
2016
The influence of SiC particles on the physical and mechanical properties for MgO/SiC composites was investigated. MgO matrix was reinforced with (2 wt%,4 wt%,6 wt % and 8 wt %) of SiC particles which synthesized using powder technology technique. Five samples of each patch have been prepared and supplied to physical properties (green density (G.D) and bulk density (B.D)) and mechanical properties (hardness and compressive strength) were measured. It was observed that the green density of all samples were decreases with increasing SiC particles content. This due to the lower density of SiC than MgO particles. Prepared samples were sintered at different temperatures (800 ˚C, 1100 ˚C, and 1450 ˚C). The bulk density reviled the unaffecting property for samples sintered at 800C and 1100˚C, but it was observed a significant increasing in B.D for samples sintered at higher temperature (1450˚C). It has been found that Vickers hardness, compressive strength and diametrical strength values in...
The Role of Heat Treatment on Characteristics of Mg-Al-Sr Reinforced Nano-SiC Composite
IOP Conference Series: Materials Science and Engineering
The effect of heat treatment on microstructure and mechanical properties of SiC/Mg-Al-Sr alloy matrix composite was investigated. The heat treatment involved annealing at 425, 375, and 325°C for 4 hours, water quenching then ageing at room temperature for 48 hours. The heat treatment process caused dissolution ofs Mg2Si precipitated and decomposition of nano-SiC particles. The composites with 0.15 Vf-% nano-SiC which was treated at 425°C has reached the optimum hardness due to precipitate of the intermetallic phase. Besides, the hardness of the treated composites still has good ductility. The fracture surface of the composite consisted of numerous dimples as a result of micro voids nucleated at the interface between the matrix and SiC particles and second-phase particles as well. The fracture of heat treated composite was similar to microvoids which were nucleated mainly on nano-SiC particles as obtained during fractography analysis.
In this study, a detailed investigation on the effect of heat treatment on the microstructural characteristics, texture evolution and mechanical properties of Mg-(5?6Tiz2?5B 4 C) BM hybrid nanocomposite is presented. Optimised heat treatment parameters, namely, heat treatment temperature and heat treatment time, were first identified through grain size and microhardness measurements. Initially, heat treatment of composites was conducted at temperature range between 100 and 300uC for 1 h. Based on optical microscopic analysis and microhardness measurements, it was evident that significant grain growth and reduction in microhardness occurred for temperatures .200uC. The cutoff temperature that caused significant grain growth/ matrix softening was thus identified. Second, at constant temperature (200uC), the effect of variation of heat treatment time was carried out (ranging between 1 and 5 h) so as to identify the range wherein increase in average grain size and reduction in microhardness occurred. Furthering the study, the effect of optimised heat treatment parameters (200uC, 5 h) on the microstructural texture evolution and hence, on the tensile and compressive properties of the Mg-(5?6Tiz2?5B 4 C) BM hybrid nanocomposite was carried out. From electron backscattered diffraction (EBSD) analysis, it was identified that the optimised heat treatment resulted in recrystallisation and residual stress relaxation, as evident from the presence of y87% strain free grains, when compared to that observed in the non-heat treated/as extruded condition (i.e. 2?2 times greater than in the as extruded condition). For the heat treated composite, under both tensile and compressive loads, a significant improvement in fracture strain values (y60% increase) was observed when compared to that of the non-heat treated counterpart, with y20% reduction in yield strength. Based on structure-property correlation, the change in mechanical characteristics is identified to be due to: (1) the presence of less stressed matrix/reinforcement interface due to the relief of residual stresses and (2) texture weakening due to matrix recrystallisation effects, both arising due to heat treatment.
Fabrication and Characterizations of Mg/SiC Composite Via Compo-Casting Technique
The present work deals with applying compo-casting technique for fabrication of magnesium matrix composite under an inert gas atmosphere. A 15 Micrometer average diameter size of -SiC particulate was used as a reinforcement material with different volume fractions. The effect of processing technique on SiC distribution within alloy matrix was investigated using light optical microscope and scanning electron microscope. Also, microstructural characterization studies conducted on the composites produced by compo-casting technique revealed a uniform distribution of SiC particulates (at the microscopic scale) and less porosity content. The mechanical properties of pure Mg and Mg-SiC composites have been evaluated. The results show a remarkable increasing in hardness value, tensile strength and 0.2% yielding strength. The increasing in overall mechanical properties revealed to SiC addition to base matrix. However, it is also evident that the strain to failure significantly decreased as the volume fraction of the particulate increased. Also, a good bonding between Mg matrix and SiC reinforcement material was observed in fracture surface SEM micrograph.