Effect of Vacuum Hot Pressing Temperature on the Mechanical and Tribological Properties of the Fe–Cu–Ni–Sn–VN Composites

Powder Metallurgy and Metal Ceramics - The mechanical (hardness and elastic modulus) and tribological (friction force and wear rate) properties of the Fe–Cu–Ni–Sn–VN...     

Effect of Cr–Mo Addition on the Microstructure and Mechanical Properties of Medium-Carbon Steel

Herein, the effects of Chromium–Molybdenum (Cr–Mo) addition on the microstructural evolution and mechanical properties of medium-carbon steel after spheroidization annealing are systematically studied through scanning electron microscopy, electron backscatter diffraction, and tensile testing. Cr–Mo addition hinders the proeutectoid ferrite + pearlite transformation, thereby promoting the bainite transformation. Moreover, it refines the pearlite lamellar spacing as well as decreases the average carbide diameter, increases the number of carbides per unit area, and hinders ferrite recrystallization. Compared with those in the B1 steel annealed for 8 h, the size of carbides and their number per unit area in the CM1 steel are 30% lower and 2.2-fold higher, respectively. Due to finer ferrite grains, smaller carbides, and a higher amount of carbides, the strength of steel improves, and the plasticity slightly reduces after Cr–Mo addition. After 2 h of annealing, the yield strengths of Cr–Mo steels are 77.5–109.5 MPa higher than those of base steels; the elongations are above 20%. The contributions of the strengthening mechanism of steel to the yield strength are as follows (from high to low): grain boundary, precipitation, solid solution, and dislocation strengthening.     

Effect of Scandium and Zirconium on Mechanical and Exfoliation Corrosion Properties of Al-Mg-Mn Alloys

To quest for the best combination of mechanical properties and exfoliation corrosion resisting property of Al-Mg-Mn base alloys, and to seek after the effect of Sc and Zr on mechanical and exfoliation corrosion properties of Al-Mg-Mn alloys, comparative research technique was used, the mechanical properties of Al-Mg-Mn alloys with and without minor Sc and Zr treated by different annealing were measured, the degrees of exfoliation corrosion for these alloys through accelerated exfoliation corrosion test were evaluated, and polarization curves of these alloys were measured, too. The micro-morphologies of corrosion specimens were observed by SEM and the corrosion product was analyzed using EDS. Optical microscope and TEM were used, the relationship between their microstruc-tures and mechanical properties, exfoliation corrosion resisting property was investigated, and the results show that the addition of minor Sc and Zr can enhance the strength greatly and also improve the combination of strength and plasticity. Moreover, the addition of minor Sc, Zr does not cause appreciable decrease of exfoliation corrosion resisting property, the Al-Mg-Mn-Sc-Zr alloy annealed at 350 ℃ for 1 h has excellent combination of mechanical properties and exfoliation corrosion resisting property, the satisfied combination of mechanical properties nad exfoliation corrosion resisting property can be obtained by means of adding minor Sc and Zr, decreasing the content of Mn, and adopting reasonable annealing practice.     

Effect of Cr and Ni/Fe Ratio on the Microstructure and Mechanical Properties of γ′-Strengthened Ni–Fe-Based Alloys

Metallurgical and Materials Transactions A - To continue to meet the future materials’ requirements for advanced power generation systems, enhancing the mechanical properties and long-term...     

Mechanical Properties and Tribological Behavior of Al6061–SiC–Gr Self-Lubricating Hybrid Nanocomposites

In the present investigation, a newly fabricated Al6061 reinforced with various quantity (0.4–1.6 wt%) of nano SiC in steps of 0.4 and fixed quantity (0.5 wt%) of micro graphite particle’s hybrid nanocomposites were prepared by ultrasonic assisted stir casting method. The influence of nano SiC and graphite content on the mechanical and tribological properties of Al6061 hybrid nanocomposites were studied. The pin-on-disc equipment was used to carry out experiment at 10–40 N applied load, 0.5 m/s sliding speed and 1000 m sliding distance. The Al/SiC/Gr hybrid nano-composite and matrix alloy wear surfaces were characterized by FESEM equipped with an EDS, 3D profilometer to understand the wear mechanisms. The results of Al/SiC/Gr self-lubricating hybrid nano-composites showed improved wear resistance than the Al6061 matrix alloy. The co-efficient of friction of Al/SiC/Gr hybrid nano-composites were lower than those of the unreinforced alloy at various applied load. Compared to matrix alloy, the surface roughness of Al/SiC/Gr hybrid nano-composites had significantly reduced to 66% at low load and 75% at high load. Self-lubricating Al/SiC/Gr hybrid nanocomposites showed superior surface smoothness compared to matrix alloy.     

Effect of Barothermal Treatment on the Structure and the Mechanical Properties of a High-Strength Eutectic Al–Zn–Mg–Cu–Ni Aluminum Alloy

The effect of barothermal treatment by hot isostatic pressing (HIP) on the structure and the properties of castings of a promising high-strength cast aluminum alloy, namely, nikalin ATs6N4 based on the Al?Zn–Mg–Cu–Ni system, has been studied using two barothermal treatment regimes different in isothermal holding temperature. It is shown that the casting porosity substantially decreases after barothermal treatment; eutectic phase Al3Ni particles are additionally refined during exposure to the barothermal treatment temperature: the higher the HIP temperature, the more substantial the refinement. The improvement of the casting structure after HIP increases their mechanical properties. It is found, in particular, that the plasticity of the alloy in the state of the maximum hardening increases by a factor of more than 8 as compared to the initial state (from 0.82 to 6.9%).     

Microstructural Features and Mechanical and Tribological Properties of Fe–Cu–Ni–Sn Composites Precipitation-Hardened with CrB2 Additions

Powder Metallurgy and Metal Ceramics - The structural features, hardness, elastic modulus, and wear resistance of Fe–Cu–Ni–Sn composites with different CrB2 contents, produced by...     

Structural,Micromechanical and Tribological Characterization of Zn–Ni Coatings: Effect of Sulfate Bath Composition

Zn and Zn–Ni alloy coatings were electrodeposited on mild steel from sulfate-based bath containing Sn as additive. The effect of Ni content on the microstructure, morphology, microhardness and the tribological behavior of these coatings were studied and discussed. Adding Sn in the sulfate bath had a significant effect on the surface morphology, particularly on the Zn–8 wt% Ni coatings. By increasing the Ni concentration from 8 to 14 wt%, the X-ray patterns showed that the phase structure of Zn–Ni alloy coatings was changed from η-phase Ni₃Zn₂₂ to γ-phase Ni₅Zn₂₁. The plastic deformation and delamination were found to be wear mechanisms for the investigated coatings. While the Zn–14 wt% Ni alloys had the best wear resistance, Zn films had the most severe wear volume loss and the highest friction coefficient.     

Properties of Electroless Ni–B and Ni–P/Ni–B Coatings Formed on Stainless Steel

In this study, Ni–P/Ni–B duplex coatings and Ni–B single layer were deposited on 410 stainless steel by the electroless process. The surface morphology and cross section observations were analyzed using scanning electron microscopy and optical microscopy. The results showed that by using the Ni–high P layer under the Ni–B deposit, the hardness value was increased. Also, the surface roughness of Ni–high P/Ni–B duplex coating was lower than the surface roughness of the Ni–B single layer. In addition, by using the Ni–high P layer as an intermediate layer prior to Ni–B coating, the surface morphology could be compressed. The mass loss diagram and the worn surfaces indicated that the Ni–high P/Ni–B duplex coating was the best wear resistant among the other coatings.     

Effect of Yttrium and Cerium Addition on Microstructure and Mechanical Properties of AM50 Magnesium Alloy

To develop magnesium alloy with low cost, high strength and excellent elevated temperature properties, effect of Y and Ce addition on microstructure and mechanical properties of AM50 magnesium alloy was studied. Result showed that addition of small amount of Y and Ce to AM50 alloys resulted in refinement of microstructure. Owing to the improvement of microstructure, the mechanical properties of alloys at both ambient and elevated temperature were increased. AM50 alloy containing 0.6 % Ce-0.3 % Y （mass fraction） had good refinement effect and relatively ideal mechanical properties.     

Influence of Strontium Addition on Microstructure and Mechanical Properties of an Al–10Si–5Cu Alloy

The microstructure and mechanical properties of Al–10Si–5Cu cast alloys with micro-addition of alloying elements (V, Cr and Ni) were studied before and after strontium addition. Samples were examined using the X-Ray diffraction, the optical microscope, the scanning electron microscope and the energy dispersive spectrometer. The results indicated that the α-Al matrix, eutectic Si phase and Al₂Cu phase were the main constituent phases of Al–10Si–5Cu alloys before or after strontium addition. Strontium addition affected the refining of the α-Al grains and transforming the configuration of interdendritic phases. The un-modified alloy showed a brittle nature because of existing brittle and aggregated AlSiMnFe phases. Contributing to the alteration of microstructure in strontium modified alloy, the strength and elongation of the alloy were improved. In addition, the fracture mechanism and crack propagation process were investigated in both the alloys.     

Effect of Electrodeposition Current and Pulse Parameter on Surface Mechanical and Electrochemical Behavior of Ni–W Alloy Coatings

Metallurgical and Materials Transactions A - Ni–W alloy coatings have various applications because they are capable of replacing hard chromium coatings due to their corrosion, oxidation,...     

Effect of Aging Time on Mechanical Properties and Wear Characteristics of Near Eutectic Al–Si–Cu–Mg–Ni Piston Alloy

Al–12Si–3Cu–1 Mg–1.78Ni alloy is widely used for piston parts in automobile industry. The present paper investigates the effect of aging time for 1–16 h at 180 °C after solution treatment of the alloy at 500 °C for 5 h, on alloys prepared by gravity casting and squeeze casting. The wear rate of the alloy shows a minimum at an intermediate aging time. The hardness and ultimate tensile strength showed a peak at intermediate aging time. Mechanical properties and wear resistance are found to be better in squeeze cast alloy. The result are explained based on the microstructure developed during casting process and on heat treatment for various durations.     

Effect of Accelerated Fe-Rich Precipitation Induced by Ag Addition on the Microstructure and Comprehensive Properties of Cu–10 Wt Pct Fe Alloys

Metallurgical and Materials Transactions A - In this study, the effect of accelerated Fe-rich precipitation caused by Ag addition on the refinement of solidified microstructure and the improvement...     

Effect of Zr Content on the Microstructure and Corrosion Resistance of Al–Cu–Mn Alloy

Russian Journal of Non-Ferrous Metals - In order to improve the overall properties of cast Al–Cu–Mn alloy, the effect of Zr content on the microstructure and corrosion resistance of...     

Effect of Yttrium on Mechanical Properties and Microstructure of Ceramets

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Effect of Deposition Temperature on the Evolution of Texture,Grain Boundary Constitution and Corrosion Behaviour of Sn–Cr Coatings

Metallurgical and Materials Transactions A - Effect of deposition temperature on the evolution of microstructure and corrosion properties of electrodeposited SnCr coatings was studied. The coatings...     

Effect of Graphite and SiC Addition into Cu and SiC Particle Size Effect on Fabrication of Cu–Graphite–SiC MMC by Powder Metallurgy

Here we have reported individual and combined effect of graphite and SiC into Cu matrix during fabrication of Cu–graphite–SiC hybrid metal matrix composite by powder metallurgy. Mechanical properties of the composites are enhanced by simultaneous addition of 1, 3, 5, 10 and 15 vol. % of graphite along with 2, 5 and 10 wt. % of SiC into pure Cu, whereas electrical conductivity deteriorates. Composites are fabricated by cold compaction of composite powder mixture followed by conventional sintering in a tubular furnace at 900 °C for 1 h in argon atmosphere. For comparison, SiC powder size of 5 and 50 µm are used to study the effect of SiC particle size on microstructure, mechanical and electrical properties of the composites. Optical microscopy and scanning electron microscopy reveal the homogeneous distribution of graphite and SiC in matrix and good compatibility between Cu–graphite and Cu–SiC particles. Hardness of the composites decreases with increase in graphite and increases with increase in SiC content. Composites containing fine SiC particles show higher hardness value as compared to coarse particles. Maximum Vickers hardness value of 75 is obtained for Cu-1 vol. % graphite-10 wt. % SiC composite. Electrical conductivity decreases with increase in both graphite and SiC content. Composites containing coarse SiC particles exhibit higher electrical conductivity than fine SiC.