Search

Highlights: [•] Directionally solidified ZrO2-mullite eutectic grown by laser floating zone. [•] Ultra-fine eutectic morphology. [•] A remarkable hardness value of 21.2GPa for the fastest as-grown fibres. [Copyright &y& Elsevier]

Highlights: [•] Formation of Ti2Ni and thermal stresses leads to formation of cracks in weld metal. [•] Sound defect-free joint could be obtained with change of fusion metal composition. [•] Inserting a copper interlayer restricts formation of the Ti2Ni in weld metal. [•] Hardness of Ti–Cu IMCs is less than hardness of Ti–Ni IMCs. [Copyright &y& Elsevier]

Highlights: [•] Study a concrete that blends two slag aggregates as an adequate raw material. [•] Making more deepen the knowledge of mix proportioning of slag concrete. [•] Study of density and workability of designed slag concrete. [•] Performance of slag concrete in a hardened state. [•] Assesses the slag concrete against the Spanish structural concrete standard. [ABSTRACT FROM AUTHOR]

Highlights: [•] We report steel alloys with several C contents obtained by mechanical alloying. [•] Increasing C content affected alloy compressibility and decreased green density. [•] Increasing C content increased hardness but decreased ductility of the alloys. [•] The maximum theoretical densification was obtained at 500MPa and 0.5% C. [ABSTRACT FROM AUTHOR]

Highlights: [•] AlN coating was applied on AISI 1045 steel via plasma nitriding and aluminizing. [•] Aluminizing of pre-nitrided specimen provides the highest surface hardness. [•] The lowest wear rate was obtained via aluminizing of pre-nitrided specimen. [•] Wear mechanism of the modified layer consists of oxidative and spallung wear. [ABSTRACT FROM AUTHOR]

Highlights: [•] The nickel has a great effect on the microstructures of the weld metals. [•] Grains were rapidly coarsened with increasing Ni content. [•] The nickel has a great effect on content and morphology of retained austenite. [•] The hardness slightly increased with increasing the rotation speed. [•] Results have shown a surprising effect of Ni content on absorbed energy. [ABSTRACT FROM AUTHOR]

Highlights: [•] The study sheds new light on the natural aging of AA7136 friction stir welds. [•] Natural aging notably influences the mechanical properties of friction stir welds. [•] The hardness profile can be correlated to the temperature distribution model. [•] The GP(I) zones formation is responsible for the increased mechanical properties. [•] Natural aging cannot be neglected in practical applications of the FSW process. [ABSTRACT FROM AUTHOR]

Highlights: [•] Alteration of metallic luster, chemical composition and crystal structure. [•] Remarkable improvement in mechanical properties. [•] A decent improvement in corrosion behavior. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ferroboron powder addition affected abrasive wear resistance positively. [•] Hard phase morphology has a major effect on wear resistance in addition to hardness. [•] Increasing FeB in powder mixture increased the hardness and the wear resistance. [•] Increasing boron content promoted the formation of primary hard phases. [Copyright &y& Elsevier]

Highlights: [•] Development of polymer/clay nanocomposites. [•] Compatibility of ABS and montmorillonite nanoclay and composition capability of them. [•] Effect of nanoclay content and process parameters on the mechanical properties of nanocomposite. [•] Analyzing the distribution of nanoclay layers using XRD test. [•] Dependency of tensile strength and hardness to the nanoclay content and processing conditions. [Copyright &y& Elsevier]

Highlights: [•] Growth of eutectic cells prevailed for lower “v” values. [•] The experimental growth formula λ 2 v = C encompasses eutectic growth. [•] Interphase spacing between Ag-rich spheroids occurred in the range 0.4–1.7μm. [•] Hall–Petch type equations are proposed relating to hardness. [Copyright &y& Elsevier]

Abstract: Polypropylene (PP) is one of the most common thermoplastic materials in the world. There is a need to recycle the large amount of this used material. To overcome the environmental problems, related to the polymer waste, PP was recycled and used as a matrix material in different composites that can be used in high value applications. In this paper, composites made of recycled polypropylene (RPP) reinforced by glass fibres and/or wood flour of the palm tree were prepared, characterized and modeled. The mechanical and thermal properties of these recycled polymer matrix composites (RPMCs) were measured experimentally and modeled theoretically. The mechanical properties included tensile modulus, tensile strength and hardness, whereas thermal properties included thermal stability, melting and crystallinity percentage content were studied. In addition we applied the functionally graded materials concept, the elastic finite element analysis of a layered functionally graded pressurized pipe, which is one of the practical industrial applications, was accomplished in order to have some insight on the performance of such RPMCs. The results reveal that the desired mechanical and thermal properties met the requirements of a wide range of practical applications which can be attained by adding the considered fillers. Also, the proper selection of the layers of the pressurized pipe, which was made of RPMCs, led to decrease of the induced stresses and accordingly increased the operational safety. [Copyright &y& Elsevier]

Highlights: [•] PN+LQ treatment results in thicker layer depth than single PN or LQ treatment. [•] The increase of layer depth is caused by the eutectoid point reduction due to introduction of N. [•] LQ treatment cause the brittle phase decomposed and the hardness redistributed of PN specimen. [•] PN+LQ specimen shows better wear resistance than the PN counterpart. [Copyright &y& Elsevier]

Abstract: Fabrication of metal-based composites with concurrent grain refinement is an exciting and novel avenue in hybrid metal manufacturing. Copper clad aluminum rods, that were fabricated using Axi-Symmetric Forward Spiral Composite Extrusion (AFSCE) are investigated here as an example. Careful investigations of the bonding mechanism in the AFSCE samples are needed to control mechanical and physical properties of the composite material. In order to understand the mechanism of the bonding between copper and aluminum in the AFSCE process, morphological and micro-structural investigations were conducted by using a Scanning Electron Microscope/Focused Ion Beam (SEM/FIB) dual ion microscope and X-ray diffraction to study the nature of the interface. Hardness measurements across the interface region of the AFSCE sample were also produced to examine the deformation mechanism. A near flawless interface, without significant intermetallic or oxide layer, was identified. The strength variation in the copper region was characterized using micro-hardness tests which agreed well with the Electron Backscatter Diffraction (EBSD) observations of various sampling points. It was also found that the micro-hardness values near the interface and the outer periphery regions of the copper were higher than the hardness values at the middle region of the material, which is approximately equal to that of unprocessed copper. [Copyright &y& Elsevier]

Highlights: [•] Hardner type, urea usage, and conditioning period of particleboard were investigated. [•] Best properties were obtained from panels manufactured with ammonium chloride. [•] The urea usage positively affected the formaldehyde emission. [•] Increasing conditioning period of panels resulted in better quality properties. [Copyright &y& Elsevier]

Highlights: [•] Melt shearing process refines the grain size and SDAS of Al–Fe alloy. [•] Increasing cooling rate refines the grain size and SDAS of Al–Fe alloy. [•] Melt shearing process improves the Al3Fe and Al6Fe intermetallic particles. [•] The hardness decreases with increasing cooling rate and times of melt shearing. [ABSTRACT FROM AUTHOR]

Highlights: [•] This work presents a novel process for successful sintering of MMC using solar energy. [•] Sintering of reinforced M2 was successful using both a Fresnel lens and a solar furnace. [•] This process allows applying lower sintering temperatures and much shorter times. [•] The nanometer sized particles would explain the high hardness values obtained. [Copyright &y& Elsevier]

Highlights: [•] Toughness of 9Cr–3W–3Co steel increases with increasing tempering temperature. [•] Toughness is influenced by hardness of base metal and length of crack propagation path. [•] Hardness of base metal is influenced by dislocation density and degree of supersaturation of the interstitial atoms. [•] Length of crack propagation path is influenced by length of the large angle boundaries. [Copyright &y& Elsevier]

Highlights: [•] Designing a net hole was effective to achieve uniform distribution SiC particles and prevent agglomeration of them. [•] SZ has fine and equiaxed grains and distribution of SiC particles in the matrix is almost uniform. [•] No intermetallic compound was formed after FSP. [•] In comparison to pure Cu, Cu/SiC composite shows higher hardness and better wear behavior. [Copyright &y& Elsevier]

Highlights: [•] Enhanced static mechanical properties for MWCNT-PC composite for minor MWCNT compositions. [•] Variation of hardness and elastic modulus with change in MWCNT composition in the composite. [•] Use of Nano-Indentor to extract nano scale properties. [•] Simple methodology for composite fabrication and composition comparison. [Copyright &y& Elsevier]

Highlights: [•] Secondary hardening occurred when tempered at 500°C and austenitized at 1050°C. [•] Hardness of new steel is about 1 HRC higher than D3 steel, when tempered at 300°C. [•] New steel has less bending strength and strain compared with D3 steel. [•] With increasing hardness wear resistance is improved about 56%. [•] Linear relationship observed between weight loss and hardness of modified steel. [ABSTRACT FROM AUTHOR]

Highlights: [•] Specific design recommendations for bobbin friction stir welding tools. [•] Pin with four flats feature best for thin plate aluminium. [•] Shoulder gap affects hence vertical flow motion. [•] Clamped side has higher hardness and lower tensile strength. [•] Developed a conceptual model representing the underlying physics. [Copyright &y& Elsevier]

Highlights: [•] Cu–P composite with micro and nano-SiC were deposited by electroless plating. [•] The coatings showed crystallisation structure. [•] The size of SiC particles did not change the structure of coatings. [•] Cu–P/nano-SiC coatings showed the best chemical, physical and mechanical properties. [Copyright &y& Elsevier]

Highlights: [•] Effects of the B contents on the peak load of the RSW in CP steels were examined. [•] The ND increased with increasing current regardless of the B contents. [•] Load in PF mode was affected by both the min. hardness and fractured diameter. [•] Load in IF mode was dependent only on the fractured diameter. [•] ND<5t 1/2 resulted in IF mode regardless of the B contents. [Copyright &y& Elsevier]

Highlights: [•] Functionally graded steel and nickel super-alloy structures have been developed. [•] Mechanical properties of FGMs can be controlled by process input parameters. [•] SDAS is strongly dependent on the laser power and powder mass flow rate. [•] Carbides provide a mechanism to control the hardness and wear resistance of FGM. [•] Tensile strength of FGM is dependent on the laser power and powder mass flow rate. [Copyright &y& Elsevier]

Highlights: [•] The Ni-base alloy was deposited on the surface of ductile iron by TIG welding process. [•] Microstructure of alloyed layer consisted of carbides embedded in Ni-rich dendrite. [•] Hardness and wear resistance of coated sample greatly improved. [•] The formation of oxide layer and delamination were dominant mechanisms of wear. [Copyright &y& Elsevier]

Highlights: [•] Microstructure and properties of the HAZ were analyzed. [•] Delta ferrite morphology changed, and ferrite content decreased. [•] Adverse effect on yield and ultimate tensile strength was negligible. [•] The absorbed energy and hardness decreases with increasing number of weld-repair. [•] The sensitivity to pitting corrosion was increased. [Copyright &y& Elsevier]

Highlights: [•] As the amount of SiC particles increase, the composite’s densification declines. [•] Increasing the amount and reducing the size of SiC lead to reduced thermal conductivity. [•] The SiC particles size decreases, the grain size and the distribution of reinforcement decreases. [•] Increasing the amount and reducing the size of SiC promote high hardness in the composite. [•] The finer particle size and increasing the amount of SiC presents greater compressive strength. [Copyright &y& Elsevier]

Highlights: [•] Deep cryogenic treatment increases the hardness and war resistance. [•] Increasing he cooling rate of quench environment, improves the hardness and wear resistance. [•] Increasing the β precipitates, improve the hardness and wear behavior. [•] Predominate wear mechanism is abrasive. [Copyright &y& Elsevier]

Abstract: Development of amorphous alloy/glassy particle reinforced light metal composites is an emerging research field. In this investigation, we have synthesized and characterized Ni60Nb40 amorphous alloy particle reinforced Mg-composites with varying volume fractions. Microwave-assisted two-directional rapid sintering technique followed by hot extrusion was used to produce these pure Mg-based composites. The structural and mechanical properties of the developed composites were investigated, and are discussed using structure–property relationship. Structural analysis indicated the retention of amorphous structure of the reinforcement in all the composites. It was found that the distribution of the reinforcement was strongly dependent on the volume fraction (Vf ). The addition of Ni60Nb40 amorphous alloy particles modified the preferred crystal orientation of Mg, as was observed from X-ray diffraction (XRD) analysis. The composites showed significant improvement in hardness (increment up to 120%) and compressive strength (∼85% increase at 5% Vf ). Comparison of mechanical properties of the developed composites with those of conventional Mg-composites having ceramic/metallic reinforcements, highlight the effectiveness of using amorphous particles as promising reinforcement materials. [Copyright &y& Elsevier]

Highlights: [•] SHS was successfully applied for TiB2–Cu composites with 5–50vol.% of Cu dilution. [•] Cu as an matrix phase was formed in whole range of investigated compositions. [•] TiB2 volume fraction significantly affected the hardness (6–18GPa). [•] TiB2:Cu ratio influenced the grain size (0.6–6.4μm in size) and microstructure. [•] Cermets with the highest TiB2 content could be competitive to WC–Co cermets. [ABSTRACT FROM AUTHOR]

Highlights: [•] In this research, kinetics of borided Nickel 201 alloy was studied. [•] It was observed that the hardness of borides formed surface of steels is over 1700HV0.05. [•] The thickness of the boride layer Nickel 201 alloys is approximately 220μm. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Y addition restrains the formation of lamellar AlLi and spheroidizes the α-Mg. [•] During the solid solution at 340°C, MgLi2Al is dissolved, and AlLi precipitates. [•] During the solid solution at 440°C, AlLi is dissolved and MgLi2Al precipitates. [•] The Y addition improves the hardness and makes the hardness become stable. [ABSTRACT FROM AUTHOR]

Highlights: [•] A reliability value can be determined from the distribution graphics of mechanical properties. [•] The percentage of damaged parts at a value of mechanical property can be determined from graphics. [•] Mechanical property values with 10%, 50% and 90% reliability were increased with sintering time. [•] MicroVickers hardness values were not increased in generally with induction sintering time. [•] It was concluded that MicroVickers hardness is not appropriate for powder metal materials. [ABSTRACT FROM AUTHOR]

Highlights: [•] Methods were proposed to clearly reveal microstructure constituents in Inconel-718. [•] In an as-forged Inconel-718 disk microstructure from center to edge was nonuniform. [•] Microstructure nonuniformities persisted after applying the common heat treatment. [•] So, for both conditions variation in hardness from center to edge of disk was seen. [•] The applied heat treatment was not effective in attaining the required hardness. [ABSTRACT FROM AUTHOR]

Highlights: [•] Formability of laser welded blanks was studied by limiting dome height test. [•] Dual-phase and high strength low alloy steel was used to prepare the welded blanks. [•] Effects of weld line position and geometry on formability of the welds was studied. [•] Failure location and formability were correlated to the hardness across the welds. [•] Softening was observed to affect formability in dual-phase steel welded blanks. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hardness is independent of general stresses at dominating plasticity. [•] Elastic deformations introduce a stress dependence of hardness. [•] Equi-biaxial tensile stresses increase stress dependence. [ABSTRACT FROM AUTHOR]

[Display omitted] • Realisation of bi-metallic laminates by wire-arc additive manufacturing. • Evaluation of design strategies for sound and defect-free deposition. • Significant impact of mutual direction of deposition on shear strength. • Performance enhancement by interlocking aided metallurgical bonding. • Limited effect of intermediate machining before second material deposition. While the recent research in manufacturing bi-metallic structures using wire and arc directed energy deposition focuses on feasibility studies to understand material compatibility, the study presented here encircles a larger design framework, integrating deposition process, intermediate surface conditions, and mutual deposition (hatching) direction. The investigation addresses the issues associated with manufacturing actual bi-metallic structures and shades light on the intrinsic mechanism responsible for process-induced anisotropy and resulting interfacial strength. Interfacial shear tests of the candidate bi-metallic pair of low-carbon steel-316L stainless steel reveal that the intermediate machining before deposition of the second material, if deposited with low dilution and low heat input has a limited effect on the final build quality. The deposition direction influences the isotropy, i.e., strength improves when the shear force acts transversely to the deposition direction of the second material. Interlocking promoted by favorable deposition direction, as revealed by fractography, combined with metallurgical bonding, enhances the interfacial strength. Despite element migration and hardness spike in the interface up to 500 HV due to martensitic needles, a defect-free bi-metallic structure was possible with shear strengths over 400 MPa. The investigation contributes to the fundamental understanding of the approaches suitable for the deposition of sound bi-metallic structures. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of multiple repairs on residual stress, microstructure and hardness for a clad plate has been studied. [•] A diffusion layer with martensite is generated around weld-base metal interface. [•] Along the weld–clad metal interface, short ferrite is generated in the fusion zone. [•] As the repair times increase, the content of short ferrite is increased. [•] It is proposed that the stainless steel clad plate cannot be repaired more than 2 times. [ABSTRACT FROM AUTHOR]

Highlights: [•] Development of shear testing procedures. [•] Characterisation of local strength and plastic behaviour of welds. [•] Assessment of local strain fields by digital image correlation. [•] Comparison of shear, tensile and hardness characterisation results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mg effects on microstructure and mechanical properties of Al–Si–Mg were studied. [•] Three alloys with different amounts were cast, homogenized and exposed to T6. [•] Intermetallic compounds were formed on the microstructure by increasing Mg amount. [•] Hardness and tensile strength increased with increasing Mg content. [•] Elongation and density decreased with increasing Mg content. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of welding velocity and pulse frequency in GMAW of HSLA steel. [•] Dependency of weldment microstructure on the welding velocity and pulse. [•] Reduction of hardness in the weld zone and HAZ with increasing of heat input. [•] The higher strength due to the higher amount of martensite. [•] Deterioration of impact properties with formation of grain boundary ferrite. [ABSTRACT FROM AUTHOR]