scholarly journals Effect of Silicon Addition on Microstructure and Mechanical Properties of Chromium and Titanium Based Coatings

2014 ◽  
Vol 23 (37) ◽  
pp. 9 ◽  
Author(s):  
Luis Carlos Ardila-Téllez ◽  
José Manuel Sánchez-Moreno ◽  
Carlos Mauricio Moreno-Téllez
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Crystallite Size ◽  
Oxidation Resistance ◽  
Columnar Structure ◽  
Size Refinement ◽  
Silicon Addition ◽  
Transmission Electron ◽  
Before And After ◽  
Size Growth

<p>The changes in the microstructure, mechanical properties and residual stresses of AlTiN, AlTiSiN, AlCrN and AlCrSiN coatings, has been studied before and after annealing at 900 ºC and 1100 ºC, using scanning and transmission electron microscopy, along with nano-indentation and X-ray diffraction techniques. The As-deposited coatings show a columnar structure, with a crystallite size between 18 nm and 28 nm. Despite the silicon addition, no effect on the crystallite size refinement was observed.<br />However, the addition of silicon increases hardness, elastic modulus and compressive residual stresses. After annealing at 900 ºC, the crystallite size growth and the residual stress relaxes; therefore, the coating hardness decreases. At 1100 ºC, the oxide layers formed in AlTiN and AlTiSiN, which act as protective layers enhancing oxidation resistance; meanwhile, a complete oxidation of AlCrN and AlCrSiN coatings take place. The Titanium based coatings present some superior mechanical properties and oxidation resistance than the chromium based coatings at 900 ºC and 1100 ºC.</p>

scholarly journals Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Przemysław Snopiński ◽  
Mariusz Król ◽  
Marek Pagáč ◽  
Jana Petrů ◽  
Jiří Hajnyš ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Equal Channel Angular Pressing ◽  
Heat Treatments ◽  
Electron Backscattered Diffraction ◽  
Angular Pressing ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Before And After ◽  
The Impact

AbstractThis study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

Synthesis of a Core-Shell Acrylate Elastomer with UV Stabilization and its Application in Polyoxymethylene

2011 ◽  
Vol 239-242 ◽  
pp. 2431-2434 ◽  
Author(s):  
Fan Yang ◽  
Gui Bo Wu ◽  
Shi Ling Zhang ◽  
Xian Cheng Ren
Keyword(s):  
Mechanical Properties ◽  
Methyl Methacrylate ◽  
Uv Irradiation ◽  
Butyl Acrylate ◽  
Core Shell ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Before And After ◽  
Uv Stabilization

In this study, a core-shell structure acrylate elastomer with UV stabilization core–shell poly[methyl methacrylate-butyl acrylate-2-hydroxy-4-(3-methacryloxy-2-hydroxylproroxy) benzophenone] [poly(MMA-BA-BPMA)] was synthesized by methyl methacrylate (MMA), butyl acrylate (BA) and a polymerizable UV-stabilizer 2-hydroxy-4-(3-methacryloxy-2-hydroxylproroxy) benzophenone (BPMA) via semicontinuous seeding emulsion polymerization. The composition and characteristics of core-shell Poly (MMA-BA-BPMA) were determined by using Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible absorption spectroscopy (UV-vis) and transmission electron microscope (TEM). Further, the obtained core-shell poly (MMA-BA-BPMA) was blended with polyoxymethylene (POM) to modify its photostabilization. The mechanical properties of POM composite were tested before and after UV-irradiation. The result showed that core-shell poly (MMA-BA-BPMA) can be dispersed well in the POM matrix, which could play a role of improving compatibility with POM and the mechanical properties of modified POM were kept well, which leaded higher impact strength and elongation at break after UV-irradiation.

scholarly journals Reduction of Residual Quenching Stresses in 2A14 Aluminum Alloy Tapered Cylinder Forgings via a Novel Cold Bulging Process

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 717
Author(s):  
Bingxiang Wang ◽  
Youping Yi ◽  
Shiquan Huang ◽  
Hailin He
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Residual Stresses ◽  
Stress Reduction ◽  
Fem Simulation ◽  
Hole Drilling ◽  
Fem Simulations ◽  
Physical Experiments ◽  
Transmission Electron ◽  
Precipitated Phases

This study combined finite element method (FEM) simulations and physical experiments to develop a novel cold bulging process, with the aim of studying and mitigating the quenching residual stresses in 2A14 tapered cylinder forgings. The samples underwent cold bulging at different ratios (0–4.0%) to evaluate the residual stress reduction performance (via the hole-drilling strain-gauge method) and the improvements in their mechanical properties. The FEM simulation and experimental results revealed that our proposed cold bulging process reduced the quenching residual stresses by up to 85–87%. The density and uniformity of the precipitated phases increased along with the extent of cold bulging, as confirmed by transmission electron microscope (TEM) observations. Furthermore, compared to the unprocessed samples, the tensile and yield strengths, and elongation of the samples with 3% cold bulging were significantly enhanced (65 MPa, 55 MPa, and 1.7%, respectively).

scholarly journals Impact of natural antioxidant systems on the oxidation resistance and mechanical properties of polypropylene

2020 ◽  
Vol 22 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Dilhumar Musajan ◽  
Maklinur Mamatjan ◽  
Riza Beken ◽  
Mamatjan Yimit
Keyword(s):  
Mechanical Properties ◽  
Oxidation Resistance ◽  
Natural Antioxidants ◽  
Raw Material ◽  
Antioxidant Systems ◽  
Oxidative Aging ◽  
Before And After ◽  
Oxidation Properties ◽  
Oxidation Resistant ◽  
Thermal Oxidative Aging

AbstractThis paper describes the separation of oxidation resistant components from the seeds of pomegranate (PSA), grape (GSE) and sea buckthorn (SSE). The anti-oxidation properties of the resultant extracts, used as the natural anti-oxidants for polypropylene (PP), were compared with Irganox1010. The effects of these natural antioxidants on the antioxidant levels of PP samples were estimated by thermal oxidative aging and micromixed rheology, OIT, XRD, SEM, TEM and mechanical properties tests of samples before and after aging. The results show that adding PSA, GSE and SSE can obviously increase the mechanical properties of PP. In addition, the molding stability of polypropylene raw material is prolonged and improved. Moreover, the mechanical properties of the PP samples after 240 h of thermal oxidative aging indicates that, the best results, closest to the anti-oxidation ability of Irganox1010, can be obtained when the additive amount is 0.5% (wt%) for PSE or 0.7% (wt%) for GSE.

scholarly journals PEEK filament characteristics before and after extrusion within fused filament fabrication process

2022 ◽  
Author(s):  
Cleiton André Comelli ◽  
Richard Davies ◽  
HenkJan van der Pol ◽  
Oana Ghita
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Extrusion Process ◽  
X Ray Diffraction ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Fast Scanning Calorimetry ◽  
Transmission Electron ◽  
Before And After ◽  
History Of

AbstractThe heating and extrusion process in fused filament fabrication (FFF) is significantly shorter than the conventional extrusion process where longer heating times and significant pressure are applied. For this reason, it is important to understand whether the crystal history of the feedstock is fully erased through the FFF process and whether the FFF process can be tailored further by engineering the crystallization of the feedstock filaments. In this context, a methodology for evaluating the influence of morphology and mechanical properties on different feedstock and extruded filaments is proposed. Filaments with three different PEEK 450G crystalline structures (standard crystallinity, drawn filament and amorphous filament) were selected and evaluated, before and after free extrusion. The resulting morphology, crystallinity and mechanical properties of the extruded filaments were compared against the feedstock properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential and fast scanning calorimetry (DSC/FDSC) and tensile test were the techniques used to evaluate the materials. The results showed clear differences in the properties of the feedstock materials, while the analysis of the extruded filaments points to a homogenization of the resulting material producing mostly similar mechanical properties. However, the use of the drawn filament highlighted a statistically significant improvement in crystallinity and mechanical performance, especially in strain values. This conclusion suggests the innovative possibility of improving the quality of manufactured parts by tailoring the microstructure of the feedstock material used in the FFF process. Graphical abstract

Microstructure and Mechanical Properties of B/Al Composite after Thermal-Mechanical Cycling

2005 ◽  
Vol 475-479 ◽  
pp. 889-892
Author(s):  
Yao Chun Qin ◽  
Shi Yu He ◽  
Dezhua
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Early Stage ◽  
Aluminum Matrix ◽  
Tensile Fracture ◽  
Dislocation Generation ◽  
Mechanical Cycling ◽  
Transmission Electron ◽  
Al Composite ◽  
Before And After

The mechanical properties of B/Al composite were measured at room temperature before and after thermal-mechanical cycling (TMC) in the temperature interval from –125°C to 125°C under constant stress of 30 MPa. The effects of TMC on microstructure and tensile fracture behavior of B/Al composite were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The fiber / matrix interfaces were degraded during TMC, the extent of which was enhanced with increasing the cycles, causing a measurable decrease of stageⅠmodulus of the B/Al composite. The TMC induced the dislocation generation in the aluminum matrix and the dislocation density increased with increasing the cycles. The tensile strength of the composites increased with the cycles in the early stage of TMC, but subsequently decreased after further TMC. The interfaces in the B/Al composite changed from the strongly-bonded toward the appropriately-bonded, and then to the weakly–bonded ones with increasing the cycles.

scholarly journals A Novel Strategy for Fabricating a Strong Nanoparticle Monolayer and Its Enhanced Mechanism

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1468
Author(s):  
Jun Zhou ◽  
Xiaoqing Cao ◽  
Linlin Li ◽  
Xingcheng Cui ◽  
Yu Fu
Keyword(s):  
Mechanical Properties ◽  
Membrane Integrity ◽  
Interparticle Distance ◽  
Grazing Incidence ◽  
Au Nanoparticle ◽  
Cross Linking ◽  
Transmission Electron ◽  
Before And After ◽  
The Cross ◽  
Novel Strategy

This work presents the preparation of cross-linking Au nanoparticle (NP) monolayer membranes by the thiol exchange reaction and their enhanced mechanical properties. Dithiol molecules were used as a cross-linking mediator to connect the adjacent nanoparticles by replacing the original alkanethiol ligand in the monolayer. After cross-linking, the membrane integrity was maintained and no significant fracture was observed, which is crucial for the membrane serving as a nanodevice. TEM (Transmission Electron Microscopy), UV–Vis absorption spectrum, and GISAXS (grazing incidence small angle X-ray scattering) were performed to characterize the nanostructure before and after cross-linking. All results proved that the interparticle distance in the monolayer was controllably changed by using dithiols of different lengths as the cross-linking agent. Moreover, the modulus of the cross-linking monolayer was measured by atomic force microscopy (AFM) and the result showed that the membrane with a longer dithiol molecule had a larger modulus, which might derive from the unbroken and intact structure of the cross-linking monolayer due to the selected appropriately lengthed dithiol. This study provides a new way of producing a nanoparticle monolayer membrane with enhanced mechanical properties.

Electrodepositing Ni-TiN/Si3N4 Composite Layer with Variation of Current Density

2020 ◽  
Vol 860 ◽  
pp. 320-326
Author(s):  
Esmar Budi ◽  
Yani Oktaviani ◽  
Achmad Fikry ◽  
Widyaningrum Indrasari ◽  
Iwan Sugihartono ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Crystallite Size ◽  
Current Density ◽  
Composite Layer ◽  
High Hardness ◽  
Maximum Hardness ◽  
Size Refinement ◽  
Crack Morphology ◽  
Two Phases

Composite of two phases with crystal grains of titanium nitride (TiN) and amorphous of silicon nitride (Si3N4) had shown an improvement of mechanical properties as shown by composite layer of nickel (Ni) and TiN. In this study, Ni-TiN/Si3N4 composite layer on tungsten carbide bar have been prepared by using electrodeposition to study the effect of current density on the microstructure and mechanical properties of the layer. The optimum properties of composite coating with no crack morphology and maximum hardness was shown by the sample electrodeposited at current density of about 2.5 mA/cm2. The high hardness was attributed to the nickel crystallite size refinement

Sign in / Sign up

Export Citation Format

Share Document