Laser alloyed Al-Ni-Fe coatings (original) (raw)
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Laser Peening on Aluminum Alloy 7049 Using Black Paint Surface Coating
˜Al-œKhawarizmi engineering journal, 2015
Black paint laser peening (bPLP) technique is currently applied for many engineering materials , especially for aluminum alloys due to high improvement in fatigue life and strength . Constant and variable bending fatigue tests have been performed at RT and stress ratio R= -1 . The results of the present work observed that the significance of the surface work hardening which generated high negative residual stresses in bPLP specimens .The fatigue life improvement factor (FLIF) for bPLP constant fatigue behavior was from 2.543 to 3.3 compared to untreated fatigue and the increase in fatigue strength at 107 cycle was 21% . The bPLP cumulative fatigue life behavior was improved by 1.786 at L-H and 1.55 at H-L due to black paint coating . Keywords: Constant and variable fatigue behavior , Black paint laser peening , 7049 Al- alloy .
Striation laser de matériaux métalliques
2005
L'objet du travail présenté est de montrer les conditions de réalisation et d'obtention de stries déterministes calibrées dans un matériau métallique hétérogène (fonte à graphite lamellaire) à l'aide d'un laser YAG. En particulier, seront décrites les stratégies d'usinage associées à la réalisation des profondeurs et des répartitions de stries désirées.
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A powder metallurgy (PM) M3, class 2, high-speed steel was subjected to surface hardening with a Nd-YAG laser. A variety of laser operating conditions, including beam size, power and travel speed, and various starting microstructural conditions, including as-annealed, as-quenched and tempered, were evaluated. Surface hardening and melting were sensitive to operating and starting conditions, but higher laser heat input into quench and tempered specimens produced significantly higher hardness, HV100, than that of bulk treated specimesn, HV860, in the as-quenched condition or HV760 in the quenched and triple tempered condition. The effects of laser surface heating on hardness and microstructure changes of the tool steel are discussed with the aid of X-Ray diffraction and Mossbauer Effect Spectroscopy (MES) data from selected specimens. Increased surface roughness marked the transition from surface hardening to surface melting.
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The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry. Résumé. Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cetteétude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique.
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Characterization and Application of Nanomaterials
In this study, nano-scale microstructural evolution in 6061-T6 alloy after laser shock processing (LSP) was studied. 6061-T6 alloy plate was subjected to multiple LSP. The LSP treated area was characterized by X-ray diffraction and the microstructure of the samples was analyzed by transmission electron microscopy. Focused Ion Beam (FIB) tools were used to prepare TEM samples in precise areas. It was found that even though aluminum had high stacking fault energy, LSP yielded to formation of ultrafine grains and deformation faults such as dislocation cells, stacking faults. The stacking fault probability (PSF) was obtained in LSP-treated alloy using X-Ray diffraction. Deformation induced stacking faults lead to the peak position shifts, broadening and asymmetry of diffraction. XRD analysis and TEM observations revealed significant densities of stacking faults in LSP-treated 6061-T6 alloy. And mechanical properties of LSP-treated alloy were also determined to understand the hardening b...
Résumé -Le but de ce travail est de modéliser et optimiser le procédé laser de texturation d'une surface métallique. Lors d'un impact laser, il se forme une plume de matière ablatée. Cette plume exerce une surpression sur la couche de métal fondu qui est ainsi repoussée vers les bords de l'impact. Dans cette étude nous présentons une modélisation thermique de l'interaction lors d'un impact laser. L'utilisation de ce modèle permet de justifier les conclusions d'une analyse statistique des résultats expérimentaux.
Very low thermal conductivity of Ti-6Al-4V begets intense localized surface heating during laser interaction which creates severe problems in laser cladding process like evaporation of material, thermal mismatch between the substrate and the pre-placed coat materials, narrow line energy zone for processing etc. In the present study an intermediate coat layer of Ni was introduced between the Ti-6Al-4V substrate and B4C, Ti powders mixture to overcome those problems. It was observed that the cladding ability of Ti-6Al-4V significantly improved due the interaction of intermediate layer. Clad layer geometry and microstructure analysis were performed by Optical Microscopy (OM) and SEM respectively. EDS and WDX elemental analysis were carried out on dispersive reinforcement particles. The presence of TiB/TiB2, TiC, TiN and Ni3Ti compositions were confirmed from HR XRD analysis.