Effect Of Silicon Addition Research Articles

Effects of Silicon Addition on Physical and Mechanical Properties of W, W–Ni, and W–Ni–Co Alloys Fabricated by Powder Metallurgy

Effects of Silicon Addition on Physical and Mechanical Properties of W, W–Ni, and W–Ni–Co Alloys Fabricated by Powder Metallurgy

Effects of Silicon addition on hardness and constituent phases of pure Magnesium synthesized by MM-SPS process

Effects of Silicon addition on hardness and constituent phases of pure Magnesium synthesized by MM-SPS process

Effect of Silicon Addition on Microstructure, Hardness and Young’s Modulus of Injection Molded AZ91D Alloy

Effect of Silicon Addition on Microstructure, Hardness and Young’s Modulus of Injection Molded AZ91D Alloy

Effect of Silicon Addition on Carbide Transition in Tempered Martensite of Middle Carbon Steels

Effect of Silicon Addition on Carbide Transition in Tempered Martensite of Middle Carbon Steels

Effect of Silicon Addition on Friction and Wear Behaviour of High Tensile Brasses

Effect of Silicon Addition on Friction and Wear Behaviour of High Tensile Brasses

Effect of silicon addition on the corrosion resistance of Al0.2CoCrFe1.5Ni high-entropy alloy in saline solution

In the paper, the effect of Si content on the microstructure evolution and corrosion properties of Al0.2CoCrFe1.5NiSix (x = 0, 0.1, 0.2, 0.3) high entropy alloys (HEAs) was systematically investigated. With the addition of Si element, the microstructure changed from single face-centered cubic (FCC) phase in the Al0.2CoCrFe1.5Ni and Al0.2CoCrFe1.5NiSi0.1 HEAs to a dual-phase structure composed of FCC and body-centered cubic (BCC) phases in the Al0.2CoCrFe1.5NiSi0.2 and Al0.2CoCrFe1.5NiSi0.3 HEAs. In addition, the corrosion mechanism has been analyzed by elemental analysis and corrosion morphology. The electrochemical measurement results indicated that the Al0.2CoCrFe1.5NiSi0.1 HEA possessed the best corrosion resistance (Ecorr = − 215 mVAg/AgCl, Icorr = 256 nA/cm2) because the small amount of Si element improves the corrosion resistance of the single-phase FCC HEA. When the Si content increased to 4.08 at% (x = 0.2) and 6.00 at% (x = 0.3), the galvanic corrosion was caused by BCC, resulting in the selective dissolution of the BCC phase and the decrease of corrosion resistance. This research results will help to understand the potential applications of doped trace Si element as a matrix element in single-phase FCC HEAs with good corrosion resistance.

Effect of Silicon Addition on Microstructure, Hardness and Young’s Modulus of Injection Molded AZ91D Alloy

Magnesium chips were coated with silicon powder using a binder, and thixomolding was attempted using the silicon-coated chips as the raw material. The microstructures of the products exhibited that all the added silicon was precipitated as Mg2Si particles. No voids were observed at the interfaces between the Mg2Si particles and the matrix. The hardness and Young's modulus of the products increased with the amount of silicon added. The Young's modulus followed the rule of mixtures.

Effect of Silicon Addition on Erosion-Corrosion Characteristics of High-Tensile Brasses

Effect of Silicon Addition on Erosion-Corrosion Characteristics of High-Tensile Brasses

Effect of silicon addition on phosphorus segregation at grain boundary and temper embrittlement of Fe-C-Mn-xSi steels

In this study, the influences silicon content on phosphorus segregation at grain boundary and temper embrittlement in Fe-C-Mn-(0.33 ∼ 2.07 wt%) Si low alloy steels are elucidated based on microstructural and mechanical characterizations. Our results demonstrate that the increase of silicon content in steels improves the ductility of the material by inhibiting the precipitation of carbides during tempered at 550 °C, but promotes the degree of phosphorus segregation at grain boundaries since the repulsive interaction of silicon and phosphorous, which is the main reason for the deterioration of impact toughness. The experimental results provide new insights into the temper embrittlement in steels with high silicon content.

Effect of silicon addition on microstructure and mechanical properties of a high strength Ti-4Al-4Mo-4Sn alloy prepared by powder metallurgy

Ti-4Al-4Mo-4Sn-xSi (wt%) (x = 0, 0.2, 0.5) alloys were fabricated by hot extrusion of compacts of blends of TiH2, AlMo60 master alloy and other required elemental powders followed by heat treatments involving vacuum annealing, solution treatment, air cooling and aging. The microstructure of the alloys consists of α plates, lamellae of α and transformed β structure (βt), βt blocks as well as grain boundary α layers. With the addition of 0.2 wt%Si, the Si atoms exist in equal concentration in both α and βt regions as solute atoms, and they retard the growth of α phase, causing a decrease of the average thickness of α plates and lamellae and slight increase of the volume fraction of βt lamellae and blocks. The solid solution strengthening and enhanced α/β interface hardening brought by the 0.2 wt%Si cause the yield strength of the Ti-4Al-4Mo-4Sn alloy to increase significantly from 1030 to 1130 MPa with a slight decrease of the tensile ductility (7.4% vs 6.8%) and without changing the fracture behavior. With the addition of 0.5 wt%Si, the extra Si causes nanometer sized silicide (Ti5Si3) precipitates to form in both α and βt regions and further microstructural refinement. The additional α/β interface hardening and precipitation hardening cause the yield strength of the alloy to increase further to 1177 MPa, but the tensile ductility deteriorates clearly with the elongation to fracture decreasing to 4.9%. The main reason for this ductility decrease is the premature fracture of grain boundary α layers caused by the higher flow stress which can induce more strain localization at the grain boundary α layers.

Excess Solute Carbon and Retained Tetragonality in Tempered Fe-0.6C-1Mn Martensite and the Effect of Silicon Addition

The tetragonality and carbon distribution in tempered Fe-0.6C-1Mn martensite were investigated by X-ray diffraction and atom probe tomography to elucidate strain relaxation in the tetragonal lattice during tempering and its relationship with the solubility of excess carbon in martensite. Even though tetragonality (c/a) decreased with an increase in the tempering temperature, it persisted at low levels up to 400 °C. Si addition suppressed the decrease in tetragonality at 400 °C by inhibiting recovery in the dislocated matrix. Such persistence implies that dislocation migration is crucial for the complete release of tetragonal lattice strain at such a temperature, in addition to the decrease in the amount of solute carbon in martensite. A low level of tetragonality was observed for martensite containing carbon in the solid solution below the critical value of ~ 0.2 mass pct, at which a bcc structure was predicted. The amount of solute carbon after tempering was linearly correlated with tetragonality in the solute carbon content range of 0.07 to 0.6 mass pct, and the correlation coefficient was similar to those for as-quenched auto-tempered martensite and bainitic ferrite; these results indicate that the amount of excess carbon is simply determined by the amount of tetragonal lattice distortions remaining after carbide precipitation and recovery.

Effect of Silicon Addition on Electrochemical Corrosion Resistance of Carbon Steel in Concrete Pore Solution

Effect of Silicon Addition on Electrochemical Corrosion Resistance of Carbon Steel in Concrete Pore Solution

Effect of silicon addition on the microstructures, mechanical properties and helium irradiation resistance of NiCoCr-based medium-entropy alloys

A series of NiCoCrSix (x = 0, 0.1, 0.2, 0.3) medium-entropy alloys were synthesized to investigate the effect of Si addition on the microstructures, mechanical properties and helium irradiation resistance of the NiCoCr-based alloys. The microstructures and the phase evolution of these alloys were examined using electron microscopy as well as the existing models. The results show that the alloys exhibit a single face-centered-cubic structure when the Si content is in the range of 0–6.25 at.%, whereas phase decomposition occurs as the Si content further increases (∼9 at.%). Comparing with NiCoCr, NiCoCrSi0.2 exhibited improved strength without sacrificing the ductility. The yield strength and ultimate tensile strength increased from 438 to 599 MPa and 921 to 1032 MPa, respectively, whilst the ductility kept as high as ∼50%. Our analysis indicates that the increased strength is mainly ascribed to the grain boundary strengthening. The large ductility is primarily due to the low stacking fault energy and shear modulus of the NiCoCrSi0.2 alloy, which makes mechanical twinning in small grains accessible and provides a steady strain-hardening rate in a wide strain regime. Besides, the enhanced compositional complexity and local lattice distortion induced by the introduction of Si can improve the helium irradiation resistance of NiCoCr, resulting in reduced average bubble size.

Effect of Silicon Addition on Corrosion Behavior of Carbon Steel Rebar in Sulfuric Acid Environment

Effect of Silicon Addition on Corrosion Behavior of Carbon Steel Rebar in Sulfuric Acid Environment

Effect of silicon addition on microstructure and mechanical properties of grey cast Iron: An overview

Grey cast iron is used to make brake disc due to its high damping vibration resistance and low cost. In the present work, effect of silicon addition on microstructure and mechanical properties of grey cast iron is reviewed. Results of microstructure and mechanical properties are compiled, which are affected due to the addition of silicon in grey cast iron. From the review, it is found that the volume of soft graphite flakes increases i.e. grain size increases which reduces the hardness of grey cast iron, on increasing the silicon content. Similarly, tensile strength reduces as a function of silicon addition. Hardness and wear rate depends on the phase of microstructure and the size of graphite flakes. Maximum hardness was obtained at 3.33% of silicon content.

Effect of silicon addition on the microstructure, mechanical and thermal properties of Cf/SiC composite prepared via selective laser sintering

Carbon fiber reinforced silicon carbide (Cf/SiC) composite was fabricated by infiltrating liquid silicon (Si) into the carbon preform, which was built by selective laser sintering (SLS) additive manufacturing process from the phenolic resin coated carbon fiber powder with addition of submicron Si. The effect of Si addition on the microstructures of the laser-sintered green part, carbon preform and derived Cf/SiC composite was investigated. The results show that the introduced submicron Si plays an important role in reducing porosity and average pore size of the carbon preform, and contributes to improving the microstructure homogeneity of Cf/SiC composite by reducing the size of continuous bulk carbon in the preforms. The maximum density, flexural strength and fracture toughness of the Cf/SiC composite are 2.89 ± 0.01 g/cm3, 237 ± 9.6 MPa and 3.56 ± 0.24 MPa m1/2, respectively. The coefficient of thermal expansion (CTE) of the Cf/SiC composite is approximately 5.5 × 10−6/K from 25 to 900 °C, and the thermal conductivity is in the range of 74–84 W/m·K at room temperature, while decreases to 35–40 W/m·K at 900 °C.

Effects of silicon addition on optical properties of mould flux with iron oxide and estimation of apparent thermal conductivity of flux

Mould flux with high absorptivity had been obtained in the reduction process of mould flux by silicon. For further utilisation of the mould flux with high absorptivity, the effect of silicon addition on the optical property has been investigated. The synthesised mould flux powder with iron oxide was melted with the addition of silicon powder at 1703 K followed by quenching, thus forming a glassy sample. After 5–30-min reduction, the samples exhibited black opaque colour. Meanwhile, the samples that were reduced for 45–60 min had a bluish grey colour. Many iron-based particles dispersed in the samples were micrometre order in diameter. To determine the effect of iron particles on the optical properties of the sample, extinction, scattering and absorption efficiencies were calculated according to Mie theory. Result showed that both scattering on the iron particle and absorption by iron effectively increase the extinction efficiency in the mould flux. Moreover, the silicon particle in the flux has large scattering efficiency. The black opaque colour is contributed by the existence of silicon and iron particles. The apparent thermal conductivity was calculated for the solid flux. Results also indicated that the entire glassy mould flux would effectively work for mild cooling in a continuous casting process owing to high absorptivity and small thermal conductivity.

The Effects of Silicon Addition on the Microstructure and Mechanical Properties of a Mg-Al-Sn Alloy Produced by Vacuum Assisted High Pressure Die Casting

In this paper, the effects of a small addition of Si (about 0.4 wt pct) on the microstructure and mechanical properties of a Mg-Al-Sn alloy produced with vacuum assisted high pressure die casting (HPDC) are reported. CALculation of PHase Diagrams-based modeling was used to design the heat treatment schedules to optimize the precipitation of Mg2Sn and Mg17Al12 in the Mg-7Al-2Sn-0.4Si alloy (in wt pct, designated as ATS). The HPDC test specimens were studied in the as-cast condition as well as in multiple heat-treated conditions to improve their tensile properties. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques were used to characterize the microstructure in each condition. The results suggest that the small addition of Si is effective in enhancing and accelerating the precipitation hardening of Mg-7Al-2Sn alloy AT72, due to enhanced precipitation of Mg17Al12 and Mg2Sn phases as well as the precipitation of Mg2Si phase. In as-cast conditions, the new ATS alloy has similar strengths but significantly improved ductility compared with AZ91D, and significantly improved strength but reduced ductility compared with AM60B. The ATS-T6 after a one-stage solution treatment provides further improvement of mechanical properties: yield strength 151 MPa, ultimate tensile strength 253 MPa, and elongation 4.9 pct.

Effect of Silicon Addition on the Properties of Carbon Fiber Reinforced Mullite Based Castable Composites

The spalling and corrosion during the thermal cycles are the main causes of the damages observed in mullite based castable composites which are used in molten iron system. Using the toughening agents of carbon fibers and the anti-oxidant of silicon, mullite based castable composites were prepared by sintering in air atmosphere. The effect of the anti-oxidant of silicon on the various physical, microstructures and mechanical properties were studied. The addition of silicon has significantly improved the cold modules of rupture and the cold crushing strength after firing at 1100 °C, but has little effect on the samples fired at 1450 °C. The cold modules of rupture and the cold crushing strength can be increased by above 20% and 30% respectively when the samples were fired at 1100 °C. After being heated in the air, the most of carbon fibers still can be found in the samples fired at 1450 °C, but can not be found in the samples fired at 1100 °C.

水稻施用硅肥对稻纵卷叶螟幼虫取食和成虫产卵选择性的影响

水稻施用硅肥对稻纵卷叶螟幼虫取食和成虫产卵选择性的影响