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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Hybrid fiber laser: arc welding of thick section high strength low alloy steel Cao, X.; Wanjara, P.; Huang, J.; Munro, C.; Nolting, A.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=19726581&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=19726581&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1016/j.matdes.2011.02.002 Materials & Design, 32, 6, pp. 3399-3413, 2011-06-01 Hybrid Fiber Laser -Arc Welding of High Strength Low Alloy Steel Abstract. High strength low alloy (HSLA) grade 80 (HSLA-80) steel with a thickness of 9.1-mm was successfully welded in a single pass using a 5-kW fiber laser combined with an arc welding process. It was found that the maximum gap size in the Y-groove butt joint configuration should remain below 0.2 mm for a 9.1-mm section thickness. Sound butt joints with no welding cracks but some minor microporosity were successfully obtained. However, an underfill defect was frequently observed on the top surface of the weldments. Underfilling could be mitigated through increasing the filler wire addition so as to exceed the groove volume; however, due to significant evaporation and expulsion of the molten pool at the high laser power density, the underfill defect would be difficult to fully eliminate. At slow cooling rates, slight softening in the heat affected zone (HAZ) was present in the mid-thickness region but its elimination is possible at high welding speeds.

Aqueous suspensions of two barium titanate (BaTiO3) powders, with 100 and 500 nm nominal size, were found to be stabilized by a predominantly steric mechanism when using a polyelectrolyte surfactant, an ammonium salt of poly(methacylate) (PMA‐NH4). Considerable amounts of barium ions were shown to readily dissolve from BaTiO3 powders in an aqueous environment, even without the addition of acid or base. This barium dissolution obscured the accurate measurement of the isoelectric point of the two powders. Suspension stabilization was observed to occur at basic pH when using PMA‐NH4. Concentrated suspensions of each individual powder exhibited shear thinning behavior, with the onset of shear thickening occurring at relatively high shear rates. Suspensions containing 85 vol% coarse/15 vol% fine powders demonstrated the lowest apparent viscosity for a given solids loading, while the highest sintered density was obtained with a mixture of 70 vol% coarse/30 vol% fine, when sintering at 1300°C for 2 h (97.4% of theoretical, slip cast from a suspension containing 50 vol% solids).

Agar was used for gel casting barium titanate (BaTiO3) ceramics. Aqueous suspensions of bimodal BaTiO3 powders, with 500 and 100 nm nominal particle sizes, were prepared with a 85:15 coarse:fine ratio. BaTiO3 suspensions were mixed with agar solutions from 2 to 8 wt%, with 0.5 or 1.0 wt% agar (as a function of BaTiO3 solids content) in the final gel‐casting suspension. BaTiO3 green densities up to ∼53.2% of theoretical were obtained. Gel casting of high aspect ratio features (up to 7:1) could be routinely performed. Cast bodies were also amenable to computer‐numerical‐controlled based green machining.

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